You are Here: Home >< Maths

# STEP Prep Thread 2016 (Mark. II)

Announcements Posted on
Why bother with a post grad? Are they even worth it? Have your say! 26-10-2016
1. Zacken , if my reasoning isn't very right or at least insufficient in a mechanics show that question (I'm talking about Q10), but I got the result they wanted with proper equations, how many marks would I lose?
2. (Original post by StrangeBanana)
I smiled when I saw it ^^

But I think I still needed to talk about there being no repeated roots; I did say f'(x) > 0 or f'(x) < 0 for roots at one point, hopefully that's enough
How'd you do the second bit about a < 0 is a is a real root? I said that for x > 0, f_(n-1) was obviously > 0, so derivative was > 0, so f_n(x) was increasing and f(0) = 1, so f_n(x) > 1, so the only real root could happen for x < 0.
3. (Original post by computerkid)
@Zacken sorry to bother you marking all these people's, but could you look at what I might have gotten for this?
19 + 4 + 3 + 13 + 20 + 20 = 79

(Original post by gagafacea1)
Zacken , if my reasoning isn't very right or at least insufficient in a mechanics show that question (I'm talking about Q10), but I got the result they wanted with proper equations, how many marks would I lose?
Not very much, maybe 4?
4. (Original post by Zacken)
How'd you do the second bit about a < 0 is a is a real root? I said that for x > 0, f_(n-1) was obviously > 0, so derivative was > 0, so f_n(x) was increasing and f(0) = 1, so f_n(x) > 1, so the only real root could happen for x < 0.
I said that fn(a)= sum of even powers of a with +ve coefficients + sum of odd powers of a with +ve coefficients =0
so since even powers > 0 the sum of odd powers <0, then factorised the sum of odd powers as a*(sum of even powers) < 0 so a<0
5. (Original post by Zacken)

Not very much, maybe 4?
Thanks!
6. Everyone here seems so experienced with STEP so I was hoping for a grade estimate Thank you and if anyone would like me to write up a solution for these I'd be more than willing

Q3: Did this one fully (including repeated roots for n is even case)

Q4: showed (ycos-sin)^2 > 4(y-1)^2 (albeit by an ugly method involving showing that (x+1/x)>= 2) and expanded some trig stuff in y^2 + 1 > 4(y-1)^2 but didn't really do anything

Q5: Fully done, although sometimes my writing may have seemed not too rigorous ("adding the different ways to make x^n from each of the sums, we need x^j from the first and x^(n-j) from the other"), but I think it was all there

Q6: Fully done

Q7: Did it all until the integral of 1/(cos(x)(cos(x)+sin(x)) which I worked with until something like 1/(cos(2x) + sin(2x) + 1), used the identity again and got nowhere xD (now that i see one just divides by cos(x) i feel so stupid haha)

Q8: Evaluated the integral at the start and drew a really rough sketch but had 1/m rather than 1/m^2 box heights and stated that clearly the area under the curve approximated the area under the boxes (possibly getting no points for the diagram)

Also I'm not sure how confident I should be of getting 20s in those I did fully :/ (looking to get 1,1 for trinity)

It seems to me like it's probably a first, but I want to be really sure (for some reasons I may have to make an important decision based on this before I get results (has to do with choosing to go to Berkeley instead and losing lots of money))
7. (Original post by Zacken)
How'd you do the second bit about a < 0 is a is a real root? I said that for x > 0, f_(n-1) was obviously > 0, so derivative was > 0, so f_n(x) was increasing and f(0) = 1, so f_n(x) > 1, so the only real root could happen for x < 0.
all terms were positive was another possibility
8. (Original post by gasfxekl)
all terms were positive was another possibility
ya that's what I did
9. (Original post by jweo)
Everyone here seems so experienced with STEP so I was hoping for a grade estimate Thank you and if anyone would like me to write up a solution for these I'd be more than willing

Q3: Did this one fully (including repeated roots for n is even case)

Q4: showed (ycos-sin)^2 > 4(y-1)^2 (albeit by an ugly method involving showing that (x+1/x)>= 2) and expanded some trig stuff in y^2 + 1 > 4(y-1)^2 but didn't really do anything

Q5: Fully done, although sometimes my writing may have seemed not too rigorous ("adding the different ways to make x^n from each of the sums, we need x^j from the first and x^(n-j) from the other", but I think it was all there

Q6: Fully done

Q7: Did it all until the integral of 1/(cos(x)(cos(x)+sin(x)) which I worked with until something like 1/(cos(2x) + sin(2x) + 1), used the identity again and got nowhere xD (now that i see one just divides by cos(x) i feel so stupid haha)

Q8: Evaluated the integral at the start and drew a really rough sketch but had 1/m rather than 1/m^2 box heights and stated that clearly the area under the curve approximated the area under the boxes (possibly getting no points for the diagram)

Also I'm not sure how confident I should be of getting 20s in those I did fully :/ (looking to get 1,1 for trinity)

It seems to me like it's probably a first, but I want to be really sure (for some reasons I may have to make an important decision based on this before I get results (has to do with choosing to go to Berkeley instead and losing lots of money))
you got into berkeley? congrats
10. (Original post by Zacken)
How'd you do the second bit about a < 0 is a is a real root? I said that for x > 0, f_(n-1) was obviously > 0, so derivative was > 0, so f_n(x) was increasing and f(0) = 1, so f_n(x) > 1, so the only real root could happen for x < 0.
I did the same thing.
11. Might as well see how people think I did:

1: Mostly full - showed there were intersections like the question asked but didn't find the exact coordinates - still think I drew an accurate sketch though.
2: Pretty confident of a full on this.
3: Happy with everything here bar the sketch justification - I think mine was very shady and rushed.
4: Wrote line one line and then decided to do a different question.
6: Everything bar the last part - differentiated v(x) and left at that.
7: All the integrals done bar the last one which I also wrote a single line for before moving on. Maybe a minor slip on one of the previous integrals but nothing massive.
12. Any solutions yet?

Posted from TSR Mobile
13. In regards to q8, How did people do part iii? i got an answer although felt like i was waffling. Overall it was a carcrash, started well with q3 getting a full. by the end managed to get 7, 2 parts of 5 what i described in q8 and two abysmal attempts at q2 and 12. Feel like i got 70 so probably a few marks below a 1
14. (Original post by fa991)
Any solutions yet?

Posted from TSR Mobile
http://www.thestudentroom.co.uk/show....php?t=4166421
15. (Original post by KingRS)
In regards to q8, How did people do part iii? i got an answer although felt like i was waffling. Overall it was a carcrash, started well with q3 getting a full. by the end managed to get 7, 2 parts of 5 what i described in q8 and two abysmal attempts at q2 and 12. Feel like i got 70 so probably a few marks below a 1
sounds similar to mine, i got 70 as well. Shamika says he think the boundary for a 1 is at 70, so we might get lucky but otherwise I feel utterly horrible.
16. (Original post by IDValour)
Might as well see how people think I did:

1: Mostly full - showed there were intersections like the question asked but didn't find the exact coordinates - still think I drew an accurate sketch though.
2: Pretty confident of a full on this.
3: Happy with everything here bar the sketch justification - I think mine was very shady and rushed.
4: Wrote line one line and then decided to do a different question.
6: Everything bar the last part - differentiated v(x) and left at that.
7: All the integrals done bar the last one which I also wrote a single line for before moving on. Maybe a minor slip on one of the previous integrals but nothing massive.
18 + 20 + 17 + 12 + 16 = 80, certainly a 1. Much better position than I'm currently in.
17. (Original post by gasfxekl)
you got into berkeley? congrats
Thank you But cambridge is my dream. Any idea for an estimate? I'm stressing hahah
18. (Original post by jweo)
Everyone here seems so experienced with STEP so I was hoping for a grade estimate Thank you and if anyone would like me to write up a solution for these I'd be more than willing
20 + 4 + 20 + 20 + 17 + 4 = 85, certainly a 1.

--

Sigh, everybody seems to be getting a 1 except me.
19. (Original post by Zacken)
20 + 4 + 20 + 20 + 17 + 4 = 85, certainly a 1.

--

Sigh, everybody seems to be getting a 1 except me.
Not the only one we can beg cambridge to let us in together haha
20. (Original post by KingRS)
Not the only one we can beg cambridge to let us in together haha
We need to do really well in STEP III to still have a reasonable chance.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: August 26, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### University open days

Is it worth going? Find out here

Poll
Useful resources