How do you solve $(1+sin theta)(1- sin theta) = cos^2 theta$ ?

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Answer 1 · 2016-09-10T02:23:41

Multiply, using the shortcut $(a + b)(a - b) = a^2 - b^2$ .

$1 - sin^2theta = cos^2theta$

Apply the pythagorean identity $sin^2theta + cos^2theta= 1 ->cos^2theta = 1- sin^2theta$ :

$1 - sin^2theta = 1 - sin^2theta$

Identity proved!

Hopefully this helps!

How do you solve (1+sin theta)(1- sin theta) = cos^2 theta(1+sin theta)(1- sin theta) = cos^2 theta?