SOLUTION: {{{(sec^2("12°")-1)tan^2(78)=1}}} prove it?

Algebra ->  Trigonometry-basics -> SOLUTION: {{{(sec^2("12°")-1)tan^2(78)=1}}} prove it?      Log On


   

Question 1034293: %28sec%5E2%28%2212%B0%22%29-1%29tan%5E2%2878%29=1 prove it?
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
%28sec%5E2%28%2212%B0%22%29-1%29tan%5E2%2878%29=1
Use a Pythagorean identity

tan%5E2%28%2212%B0%22%29tan%5E2%28%2278%B0%22%29

tan%5E2%28%2245%B0%22-%2233%B0%22%29tan%5E2%28%2245%B0%22%2B%2233%B0%22%29

Use double-angle formula:



Use tan%28%2245%B0%22%29=1







1

Edwin