Integral of cos(8x^2)? multivariable calc

[omonoid]

Integral of cos(8x^2)? multivariable calc

Homework Statement

Homework Equations

none

The Attempt at a Solution

So i reversed the order...

and couldn't figure out how to integrate cos(8x^2). I looked at my trig identities, tried on my graphing calc, and even wolfram alpha gave me a strange answer that i can't use.

Either I'm doing something wrong, or missing something obvious.

Thanks
Jake

 

[alanlu]

...dy dx?

 

[omonoid]

oh yeah. in my work i should have wrote dydx instead of dxdy good catch. wow. maybe i can solve it now.

lets see...wow... the answer was 0, after a page of work and a few hours of confusion