The Student Room Group

STEP 2 in 2024: Sharing Your Story! [PLUS WITH SOME SOLUTIONS AND PREDICTION]

FIRST EDITION:
STEP 2 is finished this year! Does anyone want to share about his performance and have guess about the score lines?

Start with me! I finished 3 full questions(calculus, series and proving), plus with two questions without the last part(polynomial, vector), and one half-finished question(graphing). I think that this paper is as difficult as the paper last year so maybe if I want to get a S, I need ~90/120.

One more interesting thing! I face difficulties when doing graphing! The first part of this question is
\left(y^{2}+\left(x-1\right)^{2}-1\right)\left(y^{2}+\left(x+1\right)^{2}-1\right)=0
and I spent about 20 minutes to find approximation and gradients until I need that if the product of two factors is 0, either one factor is 0

SECOND EDITION:
here's some strategies of solving methods, which are mentioned by us

Brief methods or comments on Q1,Q2,Q5,Q6,Q8,Q9: see at reply 17 by hauihdsf9

Brief strategies of Q2,Q6: see at reply 7 and 8 by ECFDPB

Brief method of Q5: see at reply 21 by Ticm and reply 38 by squashy123

I don't know how to quote a reply so if someone could help me, I will be really happy.
One more thing, taken our performance and the comments from some mathematics teachers in some education companies doing extra-curriculum tutorials in my country(China), I would like to have a guess on the boundary of S: around 88.

THIRD EDITION:
If you want to have a look of STEP 2 questions this year, you can find them at
GOOD LUCK FOR STEP 3!
(edited 9 months ago)

Scroll to see replies

Hi There
Im in year 12 and one of my friends did step 2 this year in year 12
how was it?
he also got distinction in BMO2
Reply 2
Original post by King Marmalade
Hi There
Im in year 12 and one of my friends did step 2 this year in year 12
how was it?
he also got distinction in BMO2

Hard to say🤣 I think I could do a better job if I can find out the method of drawing graphs immediately
Original post by ECFDPB
Hard to say🤣 I think I could do a better job if I can find out the method of drawing graphs immediately

lmao no calculator is tough
Reply 4
Original post by king marmalade
lmao no calculator is tough

you are right! I know how to solve vector problem but the amount of calculation i need to do is trouble!!!!
Reply 5
Anyway, hope everything goes well and I really want a S PLEASE!
how did you do the series question
Reply 7
Original post by jesusshuttlewort
how did you do the series question
The same strategy with 18-S2-Q5(ii), the integration of summation is equal to the summation of integration. For the last part, you need to use 'partial fraction' twice.
You are given the original equation and you need to convert 72(k-1)/(k+1)(k+2) and eventually get (x+1)/(8+x^3).
Notice that you have already known that, from the second part of the question, that 8+x^3=(x+2)(x^2-2x+4), using this result to find partial fractions. You will then get something like (-1/4x+8) + [(1/4)x+(2/3)]/(x^2-2x+4)
Don't forget that, when seeing something like [(1/4)x+(2/3)]/(x^2-2x+4), you can let u=x-1 and do the substitution, and then use arctan to find out its integration. If I'm accurate, the final answer shall be a=b=3
Reply 8
Original post by jesusshuttlewort
how did you do the series question

for another series question, about Tr, ar, br, you can finish the first several questions step by step. For the last part, notice that:
the coefficient of xn in (1-x)-3/2
= the sum of the product of 'the coefficient of xr in (1-x)-1' times 'the coefficient of xn-r in (1-x)-1/2'
= the sum of the coefficient of xr in (1-x)-1, where r from 0 to n
since after binomial expansion of (1-x)-1, the coefficient of xr is 1 for any r greater or equal to 0
By using this, we can get the answer required.
If you like, you can see similar question at:
STEP2 1999 4, STEP2 1999 8, STEP3 2007 2, STEP2 2016 5
Original post by ECFDPB
for another series question, about Tr, ar, br, you can finish the first several questions step by step. For the last part, notice that:
the coefficient of xn in (1-x)-3/2
= the sum of the product of 'the coefficient of xr in (1-x)-1' times 'the coefficient of xn-r in (1-x)-1/2'
= the sum of the coefficient of xr in (1-x)-1, where r from 0 to n
since after binomial expansion of (1-x)-1, the coefficient of xr is 1 for any r greater or equal to 0
By using this, we can get the answer required.
If you like, you can see similar question at:
STEP2 1999 4, STEP2 1999 8, STEP3 2007 2, STEP2 2016 5

thanks a lot. I don't think i got it, but i'll try to find the answer, for reference, do you remember the question
Reply 10
Original post by jesusshuttlewort
thanks a lot. I don't think i got it, but i'll try to find the answer, for reference, do you remember the question

Oh, you can check them through maths.org/step/98-S2-Q4 ,for example
(edited 9 months ago)
Reply 11
that paper i found to be so easy compared to the other years, i needed a one and i think i definately met the mark requirement but i feel like the grade boundaries will be much higher this year as all the people who sat it in my school also found it really easy. so im praying 80 should be a grade 1 hopefully they dont raise it by too much.
Reply 12
that paper i found to be so easy compared to the other years, i needed a one and i think i definately met the mark requirement but i feel like the grade boundaries will be much higher this year as all the people who sat it in my school also found it really easy. so im praying 80 should be a grade 1 hopefully they dont raise it by too much.

wait wait wait.... what? easier? do you really think so? I mean I can get 115 in 2021 STEP2, 96 in 2022 STEP2, 86 in 2023 STEP2 but I find paper this year is really TOUGH!
Original post by hauihdsf9
I'm just gonna list my thoughts overall, i'd really appreciate if anyone had anything to add.
Q1) Consecutive Numbers
P sure I got this one. Iirc, the final solutions were (35, 49) and (204, 288) for (n, k). I just remember you had to group one set of k^2 + k as 2n^2 to get the 2N'^2 = K'^2 + K equivalence, before applying it to the (6, 8) solution that you had to figure out for the first part. As long as i explained the stuff about changing k and c properly, i think i should get 20 on this.
Q2) Series Integration
Okay, so part i was basically just a bunch of manipulation. The next part was just an application of the first part, and you get the integral under question, which should be integrated to ln(3/2) i think.
This next part, I think i got the right methodology, applying partial fractions to the summation and getting 24 x ([integral] + [integral]). Then you have to write (x+1)/(x^3 + 8) [the integrand to be found] as (x+1)/(x + 2)(x^2 - 2x + 4). I majorly ****ed up and mistakenly went through the partial fractions to solve 1/(x + 2)(x^2 - 2x + 4) [I missed the x, **** my life]. Anyway, you end up getting the coefficients as multiples of 1/12, i don't remember exactly what I got. Then you get an integral of 1/(x+2) [which we found out as ln(3/2) + integral of (Bx + C)/(x^2 - 2x + 4) which you break into integral of (K(2x+2)(x^2 - 2x + 4) + M/((x-1)^2 + 4). Then you get 2 ln integrals and an arctan integral, which should get you the solution.
I'm pretty positive this is right, but how many marks do you think I lost because i calculated the wrong partial fraction? I only noticed in the last 2 seconds of the exam, its too bad. I hope I'll get at least 17, but who knows.
Q5) Ranges
I don't know why the hell I attempted this question, Im terrible with domains and ranges, I didn't know what I was doing. I majorly regret trying this, I don't even remember what I was doing. I just completed a few squares and called it a day. I think i maybe got 2 or 3 marks. Im annoyed there was no matrix question, legit my favourite types, and I'd be a lot more confident if I hadn't had to do this one, but I didn't have a ruler so I couldn't attempt the graph question and 'm not the best at vectors, so i had no choice.
Q6) Standardising summations of a_n and b_n
I think I kinda mucked this all up. I got all the answers, but I basically never did what the question asked me to. I just wrote out the expansion and managed to get all the coefficients of the forms that you required. I didn't use T_n to get a_n, and I didn't use (b_n/a_n) to find b_n. I think that's gonna dock me at least 6 marks. The final part was using the fact that (1-x)^(-1) x (1-x)^(-1/2) = (1-x)^(-3/2), which leads to the summation of a_r from r = 1 to n = b_n, which can then be manipulated to the final result.
I should have just manipulated my answers to fit the method they required us to use. Ahh.
Q8) a(n) and g(n) sequences integration
This was just inequality manipulation, I found it pretty nice. I got that y_n is bounded by M < x_0? hopefully that's right. Then as n tends to infinity, x_n - y_n tends to 0, so x_n tends to y_n which tends to M. Then the t substitution was fairly mechanical but i think it was just a standard substitution. Then you apply the I(p,q) = I((a(p,q), (g(p,q)) result to I(x_0, y_0) = I(a(x_0, y_0), g(x_0, y_0)) = I(x_1, y_1) = ... = I(x_n, y_n) as n tends to infinity. Then, as x_n and y_n tend to M, the final integral is of 1/(x^2 + M^2) from 0 to infinity, which is 1/Marctan(x/m) [infty, 0] which I got as pi/2M. Did anyone else get that?
Q9) Ditch mechanics
I think one felt a bit light? I hope I didn't miss a part. The first part was setting it so the time was when the x component reached d, and then s < 0 in the suvat at that time, it leads you straight to the result. Then you have to get tan alpha > 1 so alpha is greater than 45 degree. The next part was something similar, set the time so the x component reached 2d and then s < -2d (as it should be below the length of the wall by the time it would theoretically hit it for it to reach the bottom of the pit) which you then manipulate and you get the requisite result.
I think the final part was just showing that lambda < tan alpha < lambda + some term (I can't remember exactly) for the ball to hit the bottom of the ditch (basically just using the stuff we solved in the previous part), and as tan alpha can take all values from 1 to infinity, a suitable value of alpha can be used to satisfy the equation for all values of lambda.
I think I should have mentioned that lambda > 1 in the last part but it was proven in an earlier part (and hopefully it's implied by ' tan alpha can take valued from 1 to infinity'). Who knows.
Anyway, that's how my paper went. I think I got between 90-95 overall, I'm still annoyed that there were no matrices, they're my favourite type of question. But oh well. What do you think the S grade boundary will be? I think I'll be borderline.

i did q6 and q 8 as well. can you explain more on how you did them, because you got a waaay better answer than me
Reply 14
Original post by hauihdsf9
I'm just gonna list my thoughts overall, i'd really appreciate if anyone had anything to add.
Q1) Consecutive Numbers
P sure I got this one. Iirc, the final solutions were (35, 49) and (204, 288) for (n, k). I just remember you had to group one set of k^2 + k as 2n^2 to get the 2N'^2 = K'^2 + K equivalence, before applying it to the (6, 8) solution that you had to figure out for the first part. As long as i explained the stuff about changing k and c properly, i think i should get 20 on this.
Q2) Series Integration
Okay, so part i was basically just a bunch of manipulation. The next part was just an application of the first part, and you get the integral under question, which should be integrated to ln(3/2) i think.
This next part, I think i got the right methodology, applying partial fractions to the summation and getting 24 x ([integral] + [integral]). Then you have to write (x+1)/(x^3 + 8) [the integrand to be found] as (x+1)/(x + 2)(x^2 - 2x + 4). I majorly ****ed up and mistakenly went through the partial fractions to solve 1/(x + 2)(x^2 - 2x + 4) [i missed the x, **** my life]. Anyway, you end up getting the coefficients as multiples of 1/12, i don't remember exactly what I got. Then you get an integral of 1/(x+2) [which we found out as ln(3/2) + integral of (bx + c)/(x^2 - 2x + 4) which you break into integral of (k(2x-2)(x^2 - 2x + 4) + m/((x-1)^2 + 4). then you get 2 ln integrals and an arctan integral, which should get you the solution.
i'm pretty positive this is right, but how many marks do you think i lost because i calculated the wrong partial fraction? i only noticed in the last 2 seconds of the exam, its too bad. i hope i'll get at least 17, but who knows.
q5) ranges
i don't know why the hell i attempted this question, im terrible with domains and ranges, i didn't know what i was doing. i majorly regret trying this, i don't even remember what i was doing. i just completed a few squares and called it a day. i think i maybe got 2 or 3 marks. im annoyed there was no matrix question, legit my favourite types, and i'd be a lot more confident if i hadn't had to do this one, but i didn't have a ruler so i couldn't attempt the graph question and 'm not the best at vectors, so i had no choice.
q6) standardising summations of a_n and b_n
i think i kinda mucked this all up. i got all the answers, but i basically never did what the question asked me to. i just wrote out the expansion and managed to get all the coefficients of the forms that you required. i didn't use t_n to get a_n, and i didn't use (b_n/a_n) to find b_n. i think that's gonna dock me at least 6 marks. the final part was using the fact that (1-x)^(-1) x (1-x)^(-1/2) = (1-x)^(-3/2), which leads to the summation of a_r from r = 1 to n = b_n, which can then be manipulated to the final result.
i should have just manipulated my answers to fit the method they required us to use. ahh.
q8) a(n) and g(n) sequences integration
this was just inequality manipulation, i found it pretty nice. i got that y_n is bounded by m < x_0? hopefully that's right. then as n tends to infinity, x_n - y_n tends to 0, so x_n tends to y_n which tends to m. then the t substitution was fairly mechanical but i think it was just a standard substitution. then you apply the i(p,q) = i((a(p,q), (g(p,q)) result to i(x_0, y_0) = i(a(x_0, y_0), g(x_0, y_0)) = i(x_1, y_1) = ... = i(x_n, y_n) as n tends to infinity. then, as x_n and y_n tend to m, the final integral is of 1/(x^2 + m^2) from 0 to infinity, which is 1/marctan(x/m) [infty, 0] which I got as pi/2M. Did anyone else get that?
Q9) Ditch mechanics
I think one felt a bit light? I hope I didn't miss a part. The first part was setting it so the time was when the x component reached d, and then s < 0 in the suvat at that time, it leads you straight to the result. Then you have to get tan alpha > 1 so alpha is greater than 45 degree. The next part was something similar, set the time so the x component reached 2d and then s < -2d (as it should be below the length of the wall by the time it would theoretically hit it for it to reach the bottom of the pit) which you then manipulate and you get the requisite result.
I think the final part was just showing that lambda < tan alpha < lambda + some term (I can't remember exactly) for the ball to hit the bottom of the ditch (basically just using the stuff we solved in the previous part), and as tan alpha can take all values from 1 to infinity, a suitable value of alpha can be used to satisfy the equation for all values of lambda.
I think I should have mentioned that lambda > 1 in the last part but it was proven in an earlier part (and hopefully it's implied by ' tan alpha can take values from 1 to infinity'). Who knows.
Anyway, that's how my paper went. I think I got between 90-95 overall, I'm still annoyed that there were no matrices, they're my favourite type of question. I think this might have been a slightly easier paper as well. Damn, why were there no matrices 👿 ☹️ . But oh well. What do you think the S grade boundary will be? I think I'll be borderline.

same answer in the final part for Q8. By the way, I think, for the boundary of y_n, I prove it by showing that, as n approximates to infinite, (sqrt(x_n)-sqrt(y_n)) then to be zero, so sqrt(x_n) tends to equal to sqrt(y_n), thus y_(n+1) tends to equal to y_n.
Reply 15
Original post by hauihdsf9
I'm just gonna list my thoughts overall, i'd really appreciate if anyone had anything to add.
Q1) Consecutive Numbers
P sure I got this one. Iirc, the final solutions were (35, 49) and (204, 288) for (n, k). I just remember you had to group one set of k^2 + k as 2n^2 to get the 2N'^2 = K'^2 + K equivalence, before applying it to the (6, 8) solution that you had to figure out for the first part. As long as i explained the stuff about changing k and c properly, i think i should get 20 on this.
Q2) Series Integration
Okay, so part i was basically just a bunch of manipulation. The next part was just an application of the first part, and you get the integral under question, which should be integrated to ln(3/2) i think.
This next part, I think i got the right methodology, applying partial fractions to the summation and getting 24 x ([integral] + [integral]). Then you have to write (x+1)/(x^3 + 8) [the integrand to be found] as (x+1)/(x + 2)(x^2 - 2x + 4). I majorly ****ed up and mistakenly went through the partial fractions to solve 1/(x + 2)(x^2 - 2x + 4) [i missed the x, **** my life]. Anyway, you end up getting the coefficients as multiples of 1/12, i don't remember exactly what I got. Then you get an integral of 1/(x+2) [which we found out as ln(3/2) + integral of (bx + c)/(x^2 - 2x + 4) which you break into integral of (k(2x-2)(x^2 - 2x + 4) + m/((x-1)^2 + 4). then you get 2 ln integrals and an arctan integral, which should get you the solution.
i'm pretty positive this is right, but how many marks do you think i lost because i calculated the wrong partial fraction? i only noticed in the last 2 seconds of the exam, its too bad. i hope i'll get at least 17, but who knows.
q5) ranges
i don't know why the hell i attempted this question, im terrible with domains and ranges, i didn't know what i was doing. i majorly regret trying this, i don't even remember what i was doing. i just completed a few squares and called it a day. i think i maybe got 2 or 3 marks. im annoyed there was no matrix question, legit my favourite types, and i'd be a lot more confident if i hadn't had to do this one, but i didn't have a ruler so i couldn't attempt the graph question and 'm not the best at vectors, so i had no choice.
q6) standardising summations of a_n and b_n
i think i kinda mucked this all up. i got all the answers, but i basically never did what the question asked me to. i just wrote out the expansion and managed to get all the coefficients of the forms that you required. i didn't use t_n to get a_n, and i didn't use (b_n/a_n) to find b_n. i think that's gonna dock me at least 6 marks. the final part was using the fact that (1-x)^(-1) x (1-x)^(-1/2) = (1-x)^(-3/2), which leads to the summation of a_r from r = 1 to n = b_n, which can then be manipulated to the final result.
i should have just manipulated my answers to fit the method they required us to use. ahh.
q8) a(n) and g(n) sequences integration
this was just inequality manipulation, i found it pretty nice. i got that y_n is bounded by m < x_0? hopefully that's right. then as n tends to infinity, x_n - y_n tends to 0, so x_n tends to y_n which tends to m. then the t substitution was fairly mechanical but i think it was just a standard substitution. then you apply the i(p,q) = i((a(p,q), (g(p,q)) result to i(x_0, y_0) = i(a(x_0, y_0), g(x_0, y_0)) = i(x_1, y_1) = ... = i(x_n, y_n) as n tends to infinity. then, as x_n and y_n tend to m, the final integral is of 1/(x^2 + m^2) from 0 to infinity, which is 1/marctan(x/m) [infty, 0] which I got as pi/2M. Did anyone else get that?
Q9) Ditch mechanics
I think one felt a bit light? I hope I didn't miss a part. The first part was setting it so the time was when the x component reached d, and then s < 0 in the suvat at that time, it leads you straight to the result. Then you have to get tan alpha > 1 so alpha is greater than 45 degree. The next part was something similar, set the time so the x component reached 2d and then s < -2d (as it should be below the length of the wall by the time it would theoretically hit it for it to reach the bottom of the pit) which you then manipulate and you get the requisite result.
I think the final part was just showing that lambda < tan alpha < lambda + some term (I can't remember exactly) for the ball to hit the bottom of the ditch (basically just using the stuff we solved in the previous part), and as tan alpha can take all values from 1 to infinity, a suitable value of alpha can be used to satisfy the equation for all values of lambda.
I think I should have mentioned that lambda > 1 in the last part but it was proven in an earlier part (and hopefully it's implied by ' tan alpha can take valued from 1 to infinity'). Who knows.
Anyway, that's how my paper went. I think I got between 90-95 overall, I'm still annoyed that there were no matrices, they're my favourite type of question. But oh well. What do you think the S grade boundary will be? I think I'll be borderline.

yeah i aggree with what you wrote mostly im so glad i found the mechanics quite easy, im failry sure i got 40 on those questions i know some people found them tricky, but i dont know i just figured out how to do them in the test. like it just came to me xD
Reply 16
yeah i aggree with what you wrote mostly im so glad i found the mechanics quite easy, im failry sure i got 40 on those questions i know some people found them tricky, but i dont know i just figured out how to do them in the test. like it just came to me xD

really? Mechanism is easy? Oh god no! The final boundary will rise because of that😭 I never read any questions about Mechanism and Statistics
Reply 17
I'm just gonna list my thoughts overall, i'd really appreciate if anyone had anything to add.

Q1) Consecutive Numbers

P sure I got this one. Iirc, the final solutions were (35, 49) and (204, 288) for (n, k). I just remember you had to group one set of k^2 + k as 2n^2 to get the 2N'^2 = K'^2 + K equivalence, before applying it to the (6, 8) solution that you had to figure out for the first part. As long as i explained the stuff about changing k and c properly, i think i should get 20 on this.

Q2) Series Integration

Okay, so part i was basically just a bunch of manipulation. The next part was just an application of the first part, and you get the integral under question, which should be integrated to ln(3/2) i think.This next part, I think i got the right methodology, applying partial fractions to the summation and getting 24 x ([integral] + [integral]). Then you have to write (x+1)/(x^3 + 8) [the integrand to be found] as (x+1)/(x + 2)(x^2 - 2x + 4). I majorly ****ed up and mistakenly went through the partial fractions to solve 1/(x + 2)(x^2 - 2x + 4) [i missed the x, **** my life]. Anyway, you end up getting the coefficients as multiples of 1/12, i don't remember exactly what I got. Then you get an integral of 1/(x+2) [which we found out as ln(3/2) + integral of (bx + c)/(x^2 - 2x + 4) which you break into integral of (k(2x-2)(x^2 - 2x + 4) + m/((x-1)^2 + 4). then you get 2 ln integrals and an arctan integral, which should get you the solution.i'm pretty positive this is right, but how many marks do you think i lost because i calculated the wrong partial fraction? i only noticed in the last 2 seconds of the exam, its too bad. i hope i'll get at least 17, but who knows.

q5) ranges

i don't know why the hell i attempted this question, im terrible with domains and ranges, i didn't know what i was doing. i majorly regret trying this, i don't even remember what i was doing. i just completed a few squares and called it a day. i think i maybe got 2 or 3 marks. im annoyed there was no matrix question, legit my favourite types, and i'd be a lot more confident if i hadn't had to do this one, but i didn't have a ruler so i couldn't attempt the graph question and 'm not the best at vectors, so i had no choice.

q6) standardising summations of a_n and b_n

i think i kinda mucked this all up. i got all the answers, but i basically never did what the question asked me to. i just wrote out the expansion and managed to get all the coefficients of the forms that you required. i didn't use t_n to get a_n, and i didn't use (b_n/a_n) to find b_n. i think that's gonna dock me at least 6 marks. the final part was using the fact that (1-x)^(-1) x (1-x)^(-1/2) = (1-x)^(-3/2), which leads to the summation of a_r from r = 1 to n = b_n, which can then be manipulated to the final result.i should have just manipulated my answers to fit the method they required us to use. ahh.

q8) a(n) and g(n) sequences integration

this was just inequality manipulation, i found it pretty nice. i got that y_n is bounded by m < x_0? hopefully that's right. then as n tends to infinity, x_n - y_n tends to 0, so x_n tends to y_n which tends to m. then the t substitution was fairly mechanical but i think it was just a standard substitution. then you apply the i(p,q) = i((a(p,q), (g(p,q)) result to i(x_0, y_0) = i(a(x_0, y_0), g(x_0, y_0)) = i(x_1, y_1) = ... = i(x_n, y_n) as n tends to infinity. then, as x_n and y_n tend to m, the final integral is of 1/(x^2 + m^2) from 0 to infinity, which is 1/marctan(x/m) [infty, 0] which I got as pi/2M. Did anyone else get that?

Q9) Ditch mechanics

I think one felt a bit light? I hope I didn't miss a part. The first part was setting it so the time was when the x component reached d, and then s < 0 in the suvat at that time, it leads you straight to the result. Then you have to get tan alpha > 1 so alpha is greater than 45 degree. The next part was something similar, set the time so the x component reached 2d and then s < -2d (as it should be below the length of the wall by the time it would theoretically hit it for it to reach the bottom of the pit) which you then manipulate and you get the requisite result.

I think the final part was just showing that lambda < tan alpha < lambda + some term (I can't remember exactly) for the ball to hit the bottom of the ditch (basically just using the stuff we solved in the previous part), and as tan alpha can take all values from 1 to infinity, a suitable value of alpha can be used to satisfy the equation for all values of lambda.I think I should have mentioned that lambda > 1 in the last part but it was proven in an earlier part (and hopefully it's implied by ' tan alpha can take valued from 1 to infinity'). Who knows.

Anyway, that's how my paper went. I think I got between 90-95 overall, I'm still annoyed that there were no matrices, they're my favourite type of question. Im so annoyed man :frown:. But oh well. What do you think the S grade boundary will be? I think I'll be borderline.

NOTE - I think my earlier comment deleted, so I've just recopied it.

I usually get ~115 in the 2019-2023 past papers, I think i'd have gotten similar if there was a matrix or a differential equation question which I could have answered, but regardless, I think this paper might have genuinely been slightly easier. I'll just assume S is like 95 at this point.
(edited 9 months ago)
Reply 18
Original post by hauihdsf9
I'm just gonna list my thoughts overall, i'd really appreciate if anyone had anything to add.
Q1) Consecutive Numbers
P sure I got this one. Iirc, the final solutions were (35, 49) and (204, 288) for (n, k). I just remember you had to group one set of k^2 + k as 2n^2 to get the 2N'^2 = K'^2 + K equivalence, before applying it to the (6, 8) solution that you had to figure out for the first part. As long as i explained the stuff about changing k and c properly, i think i should get 20 on this.
Q2) Series Integration
Okay, so part i was basically just a bunch of manipulation. The next part was just an application of the first part, and you get the integral under question, which should be integrated to ln(3/2) i think.This next part, I think i got the right methodology, applying partial fractions to the summation and getting 24 x ([integral] + [integral]). Then you have to write (x+1)/(x^3 + 8) [the integrand to be found] as (x+1)/(x + 2)(x^2 - 2x + 4). I majorly ****ed up and mistakenly went through the partial fractions to solve 1/(x + 2)(x^2 - 2x + 4) [i missed the x, **** my life]. Anyway, you end up getting the coefficients as multiples of 1/12, i don't remember exactly what I got. Then you get an integral of 1/(x+2) [which we found out as ln(3/2) + integral of (bx + c)/(x^2 - 2x + 4) which you break into integral of (k(2x-2)(x^2 - 2x + 4) + m/((x-1)^2 + 4). then you get 2 ln integrals and an arctan integral, which should get you the solution.i'm pretty positive this is right, but how many marks do you think i lost because i calculated the wrong partial fraction? i only noticed in the last 2 seconds of the exam, its too bad. i hope i'll get at least 17, but who knows.
Q5) ranges
i don't know why the hell i attempted this question, im terrible with domains and ranges, i didn't know what i was doing. i majorly regret trying this, i don't even remember what i was doing. i just completed a few squares and called it a day. i think i maybe got 2 or 3 marks. im annoyed there was no matrix question, legit my favourite types, and i'd be a lot more confident if i hadn't had to do this one, but i didn't have a ruler so i couldn't attempt the graph question and 'm not the best at vectors, so i had no choice.
Q6) standardising summations of a_n and b_n
i think i kinda mucked this all up. i got all the answers, but i basically never did what the question asked me to. i just wrote out the expansion and managed to get all the coefficients of the forms that you required. i didn't use t_n to get a_n, and i didn't use (b_n/a_n) to find b_n. i think that's gonna dock me at least 6 marks. the final part was using the fact that (1-x)^(-1) x (1-x)^(-1/2) = (1-x)^(-3/2), which leads to the summation of a_r from r = 1 to n = b_n, which can then be manipulated to the final result.i should have just manipulated my answers to fit the method they required us to use. ahh.
q8) a(n) and g(n) sequences integration
this was just inequality manipulation, i found it pretty nice. i got that y_n is bounded by m < x_0? hopefully that's right. then as n tends to infinity, x_n - y_n tends to 0, so x_n tends to y_n which tends to m. then the t substitution was fairly mechanical but i think it was just a standard substitution. then you apply the i(p,q) = i((a(p,q), (g(p,q)) result to i(x_0, y_0) = i(a(x_0, y_0), g(x_0, y_0)) = i(x_1, y_1) = ... = i(x_n, y_n) as n tends to infinity. then, as x_n and y_n tend to m, the final integral is of 1/(x^2 + m^2) from 0 to infinity, which is 1/marctan(x/m) [infty, 0] which I got as pi/2M. Did anyone else get that?
Q9) Ditch mechanics
I think one felt a bit light? I hope I didn't miss a part. The first part was setting it so the time was when the x component reached d, and then s < 0 in the suvat at that time, it leads you straight to the result. Then you have to get tan alpha > 1 so alpha is greater than 45 degree. The next part was something similar, set the time so the x component reached 2d and then s < -2d (as it should be below the length of the wall by the time it would theoretically hit it for it to reach the bottom of the pit) which you then manipulate and you get the requisite result.
I think the final part was just showing that lambda < tan alpha < lambda + some term (I can't remember exactly) for the ball to hit the bottom of the ditch (basically just using the stuff we solved in the previous part), and as tan alpha can take all values from 1 to infinity, a suitable value of alpha can be used to satisfy the equation for all values of lambda.I think I should have mentioned that lambda > 1 in the last part but it was proven in an earlier part (and hopefully it's implied by ' tan alpha can take valued from 1 to infinity'). Who knows.
Anyway, that's how my paper went. I think I got between 90-95 overall, I'm still annoyed that there were no matrices, they're my favourite type of question. Im so annoyed man :frown:. But oh well. What do you think the S grade boundary will be? I think I'll be borderline.
NOTE - I think my earlier comment deleted, so I've just recopied it.

Yes you DO delete your original post lol🤣 But I have to admit, your post is really amazing and thanks for your explanation!
Reply 19
Original post by ECFDPB
same answer in the final part for Q8. By the way, I think, for the boundary of y_n, I prove it by showing that, as n approximates to infinite, (sqrt(x_n)-sqrt(y_n)) then to be zero, so sqrt(x_n) tends to equal to sqrt(y_n), thus y_(n+1) tends to equal to y_n.

IIRC, There was a premise in the question that showed that a sequence tends to a limit L if it bounded by some value b, so L < b. So i just manipulated the sequence to find a value of b that would act as the bound value, which I found as x_0, thus M < x_0 But yea, your methods probably right anyway.

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