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C1 help!

Just did a Paper E of the soloman papers and the mark scheme seems to be corrupt:angry: If anyone has the markscheme could they post it here? and if you don't could you help me with the questions?

So there are a few questions which I really couldn't do



For this I could not do part C, I got (0, -1) which is defin wrong, I got this by equating the two equations




This is for part B, I differentiated from the earlier equation and got

(3/4) x ^(1/2) -2x^(-1/2) -4x^ (-3/2)

But not sure how I would rearrange this to get it in the form that they want




Lastly need help with part b, I got the gradient as 10 but couldn't get to the equation they wanted I got y = 10x - 2

For the contact part I got dy/dx and made it equal to 10, I then solved and got
x = 1
or
x= -7/3

Corresponding y values I got were 0 and -229/27



Thanks guys
Reply 1
Avatar for isp
isp
8. C)

When you equate the two equations you should end up with 2x2−2x−12x^2 - 2x - 1. Use the quadratic formula to factorise this and get it in the form a+b3a + b\sqrt3

7. B) Highly doubt that would come up in a C1 exam paper as half the candidates wouldn't be able to answer it

10. B) It says to show the line y = x - 2 is a tangent to C

What's C? C is the equation of the line which you should have got in part a) when you integrated the dy/dx and found k
(edited 11 years ago)
Reply 2
Avatar for 0range
0range
OP
20
Original post by isp
8. C)

When you equate the two equations you should end up with 2x2−2x−12x^2 - 2x - 1. Use the quadratic formula to factorise this and get it in the form a+b3a + b\sqrt3

7. B) Highly doubt that would come up in a C1 exam paper as half the candidates wouldn't be able to answer it

10. B) It says to show the line y = x - 2 is a tangent to C

What's C? C is the equation of the line which you should have got in part a) when you integrated the dy/dx and found k



Urmm C is x^3 +2x^2 +2x -2


How did you get 2x2−2x−12x^2 - 2x - 1 ?
Reply 3
Avatar for isp
isp
Original post by 0range
Urmm C is x^3 +2x^2 +2x -2


How did you get 2x2−2x−12x^2 - 2x - 1 ?


Alright I wrote it on paper as I cannot be bothered with latex.

Spoiler



For question 10)

Yes for C that is correct it is x3+2x2+2x−2x^3 + 2x^2 + 2x - 2

Now equal both of them together and you get x3+2x2+2x−2=x−2x^3 + 2x^2 + 2x - 2 = x - 2

x3+2x2+x=0x^3 + 2x^2 + x = 0

Now factorise this

hint:

Spoiler

Reply 4
Avatar for 0range
0range
OP
20
Original post by isp
Alright I wrote it on paper as I cannot be bothered with latex.

Spoiler



For question 10)

Yes for C that is correct it is x3+2x2+2x−2x^3 + 2x^2 + 2x - 2

Now equal both of them together and you get x3+2x2+2x−2=x−2x^3 + 2x^2 + 2x - 2 = x - 2

x3+2x2+x=0x^3 + 2x^2 + x = 0

Now factorise this

hint:

Spoiler



Ahh yup that's wicked, Thank you!!!
For question 7b youi can just use the quotient rule

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