CALCULUS (REPOST)
posted by Anonymous on .
If dy/dx = x (cos x^2) and y = −3 when x = 0, when x = pi, y = .
A. −3.215
B. sqrt(2)
C. 1.647
D. 6
E. 3pi
For some odd reason, I keep getting 0.5325989. I can't come up with any of the answers given.

I=∫ xcos(x²)dx
sub u=x², du=2xdx
I=∫cos(u)du/2
=sin(u)/2+C
When x=0, u=0, y=3 => C=3
so
y=sin(x²)/23
So calculate
y=sin(π²)3
Note that if you use your calculator, make sure you put the angle to be in radians mode to get the correct answer. 
y=sin(pi^2)3 yields approximately 3.430301217, which still doesn't fit the bill for the options I am given.

Sorry that there was a typo (I forgot to divide sin(x²) by 2):
y=sin(x²)/23
So calculate
y=sin(π²)/23