Can someone help me prove these two identities?
I have to prove these two identities and they're really giving me a hard time :/
I need to see all the steps taken.
1) sin^4 β - cos^4 β = 1 - 2cos^2 β
2) cos Φ/(1 + sinΦ) + (1 + sin Φ)/cos Φ = 2sec Φ
thank youuuu!
Thank you Soroban!
And e^(i*pi), I was told I had to use trigonometric identity formulas and i have to prove that, for number one,
sin^4 β - cos^4 β = 1 - 2cos^2 β
that the Left side and the right side are truly equal to each other. I still don't understand. :|
Hi dlngoal:
I did this for you a few days ago. here's the link:
http://www.mathhelpforum.com/math-he...-identity.html