# math

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Sin 3x=3 sin x-4 sin^3 x

• math -

sin 3x
sin2x cosx + cos2x sinx
2sinx cosx cosx + (1 - 2sin^2 x)sinx
2sinx cos^2 x + sinx - 2sin^3 x
2sinx (1-sin^2 x) + sinx - 2sin^3 x
2sinx - 2sin^3 x + sinx - 2sin^3 x
3sinx - 4sin^3 x

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