Double integral of cos(x²) with triangular region

[elvishatcher]

Can someone explain to me how I would arrive at this answer?:
http://www.wolframalpha.com/input/?...m+x=y+to+x=sqrt(pi/2)+and+y=0+to+y=sqrt(pi/2)

This double integral problem came up in a practice test I was taking, and I just can't figure it out. I tried integrating it but couldn't figure out how to integrate cos(x^2)dx and when I put that into Wolfram Alpha it said it involved some special function that seems much too advanced for the level of the course the test is from (it's from a first year multivariable calculus class). Thanks!

 

[LCKurtz]

Can someone explain to me how I would arrive at this answer?:
http://www.wolframalpha.com/input/?...m+x=y+to+x=sqrt(pi/2)+and+y=0+to+y=sqrt(pi/2)

This double integral problem came up in a practice test I was taking, and I just can't figure it out. I tried integrating it but couldn't figure out how to integrate cos(x^2)dx and when I put that into Wolfram Alpha it said it involved some special function that seems much too advanced for the level of the course the test is from (it's from a first year multivariable calculus class). Thanks!

Draw the region then use your picture to reverse the order of integration.

 

[elvishatcher]

Aha, got it. Thanks much.