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Prove the following identities

Quote: Originally Posted by purplec16 Prove the following identities Use the formula cos(2θ) = 1 - 2sin^2(θ) Or 2sin^2(θ) = 1 -cos(2θ And sin(2θ) = 2sinθcosθ For second problem use sinA - sinB = 2cos[(A+B)/2]*sin[(A-B)/2] cosA - cosB = -2sin[(A+B)/2]*sin(A-B)/2]