looks like you forgot about the 4 in the original integral
So I got tan^(-1)x ] 0 to 1<-- supposed to be inverse tanx evaluated from 0 to 1.
Inverse tan of 1 is pi/4 minus inverse tan of 0 is 0, so I end up with pi/4 as the answer. The book says the answer is pi... What am I doing wrong?
Ah, thanks. I knew that the four would cancel somehow, I just didn't know that you could take it out like that.
Also, what's a derivative of an integral? I know how to find it, but what exactly is it? If I understand correctly, an integral is the area between the x-axis and the function, so what information would the derivative of that yield?