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.
cos^4(at) = 3/8 + 1/2cos(2at) + 1/8cos(4at)
cos^4(at) = 3/8 + 1/2cos(2at) + 1/8cos(4at)
Natural Language
Math Input
Extended Keyboard