Cosx in terms of tanx

identities of the double angle as the corner considered is a multiple of 2, ie double x. We write the identity COS 2X in different forms: so 2x = COS2X â € "sin2x so 2x = 2cos2x â €" 1 so 2x = 1 â € "2Sin2x derivation of COS 2X using the an addition formula of the corners we know that so 2x It can be expressed in four different forms. ................
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