Answers

2015-11-25T11:13:33+05:30
Using , quadrant concept :-

sin(3π/2-x) = -cosx
sin(3π/2 + x) = -cosx

sin(π/2 + x) = cosx

sin(5π-x) = sinx

⇒ 3(cos²x + cos²x) - 2(cos²x+sin²x)

⇒ 3(2cos²x ) - 2
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