Can you prove $1- \cos ^ { 2} x = \sin x \cos x \tan x$ ?

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Answer 1 · 2017-03-26T22:15:27

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Recall that $tanx=sinx/cosx$ and the Pythagorean identity $sin^2x+cos^2x=1$

From the identity it can be determined that $sin^2x=1-cos^2x$

$sinxcosxtanx=sinxcosx(sinx/cosx)=sinxsinx=sin^2x=1-cos^2x$

$1-cos^2x=1-cos^2x$

$"Q.E.D."$

Can you prove 1- \cos ^ { 2} x = \sin x \cos x \tan x1- \cos ^ { 2} x = \sin x \cos x \tan x?