Can somebody help me out with this maths questio

[Ahsen420]

http://www.xtremepapers.me/CIE/Cambridg ... 8_qp_2.pdf
Q19(b)

I have maths P22 tomorrow, wish me luck. I hope its not 2 much difficult

 

[Smile27]

This has already been answered...?

 

[TSZ]

hey where was it answered, plzzz tell me