<p>So, I have this integral that I have to solve. When I plug it into the calc I come up with a negative answer. I solved it by hand without breaking it apart and came up with the same negative answer, -.035555281. I tried to break it apart and solve in pieces and came up with a different answer .088855645. If anyone can solve this and tell me if I am right or wrong it would be greatly appreciated.</p>
<p>The integral is... (x^2)(sin(9x))dx from 0 to pi/4</p>
<p>I found the zeros of the function to be 0, pi/9, and 2pi/9 and solved to get the second answer, but I am not sure if I did it correctly. </p>
<p>To get the second answer I did the absolute value of the negative section plus the two positive sections.</p>