Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
int r*(4r^2+1)^(1/2) drdt r from 0 to 1 t from pi/4 to pi/2
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random