Question 681619: Alright this is kinda a long question and I am hoping you can help me out
Prove that (1-tan^2 x) / (1+tan^2 x) = cos 2 x
For each step of the proof I also need to know what rule this applies to (algebra, reciprocal, quotient, Pythagorean, double angel, or sum and differences).
Thank you so so much for your help!
Answer by solver91311(24713)   (Show Source):
You can put this solution on YOUR website!
}{\cos^2\varphi\ +\ \sin^2\varphi})
}{1}\ =\ \cos(2\varphi))
By the way, if you want to know about the "double angel" formula, consult your local priest, minister, pastor, imam, rabbi, tribal shaman, or whatever passes for a cleric in your personal tradition. Trigonometry is concerned with angles.
John
Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
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