# trig

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how do you do sinAcosA=cosA-cos^3A/sinA

• trig -

divide each term by cosA
sinA = 1 - cos^2A/sinA
multiply each term by sinA
sin^2A = sinA - cos^2A
sin^2A = sinA - (1 - sin^2A)
1 = sinA
A = 90º or pi/2 radians

or in general:
A = k(90)º or k(pi/2) radians

• trig -

A = pi/2 + 2 n pi radians. n is any integer, including zero

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