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How do you verify the identity: $sin 2 x = (tan x) (1 + cos 2 x)$ $sin2x=(tanx)(1+cos2x)$ ?

1 Answer

Apr 28, 2015

Use the trig identity: $(1 + cos 2 a) = 2 {cos}^{2} a$ $(1 + cos 2a) = 2 cos^2 a$ .

$tan x . (1 + cos 2 x) =$ $tan x.(1 + cos 2x) =$ (sin x/cos x) $. 2 {cos}^{2} x$ $. 2cos^2 x$ =
= 2.sin x . cos x = sin 2x#.

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