solving equation using mathematical induction

Oct 2012
10
0
europe
solving trigonometric equation using mathematical induction

Prove that this is true for every n. (n is an element of natural numbers)

cos(n*pi) = (-1)^n

I would very much appreciate your help, thank you.
 
Last edited:
Sep 2012
1,061
434
Washington DC USA
Re: solving trigonometric equation using mathematical induction

\(\displaystyle \text{Use: } \cos((n+1) \pi ) = \cos(n\pi + \pi) = \cos(n\pi)\cos(\pi) - \sin(n\pi)\sin(\pi), \text{ and continue on from there.}\)
 
Last edited:
Oct 2012
10
0
europe
Re: solving trigonometric equation using mathematical induction

Thank you for your help.