i have been able to do the following
But I'm stuck in simplifying the equation
See my working below
[MATH]\cos3x+i\sin3x=\cos^3x+3i\cos^2x\sin x-3\cos x\sin^2x-i\sin^3x [/MATH]
[MATH] \begin{align} \sin3x&=3\cos^2x\sin x-\sin^3x \\[6px] \cos3x&=\cos^3x-3\cos x\sin^2x \\[12px] \tan3x&=\frac{3\cos^2x\sin x-\sin^3x}{\cos^3x-3\cos x\sin^2x} \end{align} [/MATH]
[MATH] \tan(3x)=\frac{3\tan(x)-\tan^3(x)}{1-3\tan^2(x)} [/MATH]
But I'm stuck in simplifying the equation
See my working below
[MATH]\cos3x+i\sin3x=\cos^3x+3i\cos^2x\sin x-3\cos x\sin^2x-i\sin^3x [/MATH]
[MATH] \begin{align} \sin3x&=3\cos^2x\sin x-\sin^3x \\[6px] \cos3x&=\cos^3x-3\cos x\sin^2x \\[12px] \tan3x&=\frac{3\cos^2x\sin x-\sin^3x}{\cos^3x-3\cos x\sin^2x} \end{align} [/MATH]
[MATH] \tan(3x)=\frac{3\tan(x)-\tan^3(x)}{1-3\tan^2(x)} [/MATH]
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