SOLUTION: Given sin (x+y)= sin x cos y + cos x sin y
and cos(x+y) = cos x cos y -sin x sin y
derive a formula for cos(2x)
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Question 1111748: Given sin (x+y)= sin x cos y + cos x sin y
and cos(x+y) = cos x cos y -sin x sin y
derive a formula for cos(2x)
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
derive a formula for cos(2x)
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cos(2x) = cos(x+x) = cos*cos - sin*sin = cos^2(x) - sin^2(x)
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