Can someone prove this for me, please show enough steps so that i know what your doing along the way. Thanks sin3x=3sinx-4sin^3x - the x isn't with ^3.
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$\displaystyle \sin 3x=\sin (2x+x)$ and use the formula $\displaystyle \sin(a+b)=\sin a\cos b+\sin b\cos a$ and $\displaystyle \sin 2x=2\sin x\cos x, \ \cos 2x=1-2\sin^2x$
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