Question

Help with question 7i pleaseee! http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Mathematics%20(9709)/9709_s07_qp_3.pdf

Answer 1

So, u = sqrt x
du/dx = 1/2sqrtx

Answer 2

ok now find dx

Answer 3

I = 1/u^-1/2 (4-u) 2sqrt u du ?

Answer 4

dx = 2x^1/2 du

Answer 5

im talking about the overall.

Answer 6

ok - bear with me - its been a while since i did these

Answer 7

Aites.

Answer 8

dx = 2u du

Answer 9

i'll have to just do small posts as thers something wrong with the website

Answer 10

wait dx is wht again?

Answer 11

u = sqrt x so x = u^2
so if we substite in the integral

Answer 12

@welshfella - i get that all the time, the Post button disappears. i have tried Safari, Chrome and it is soooo frustrating.....

Answer 13

yes its murder
dx = 2u.du

Answer 14

not dx = u.du - my mistake

Answer 15

delete the wrong one pls. haha thanks.