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.
using induction%2C prove 9%5En-1 is divisible by 4 assuming n%3E0
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random
