Kenneth S. answered • 03/18/17
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Expert Help in Algebra/Trig/(Pre)calculus to Guarantee Success in 2018
Show that sin^2x-cos^2x=2sin^2x-1 by working on left hand side. Note: will use well known double angle formulas.
LHS = -cos 2x = - (1 - 2 sin2x) which after distribution becomes RHS. QED
Kenneth S.
there are three forms of cos 2x:
= cos2x - sin2x and then, based on Pythagorean identity sin2x + cos2x = 1, there are two alternative forms:
= 1 - 2 sin2x
= 2cos2x -1.
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03/18/17
Cody C.
03/18/17