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Prove the following identity: cos^3theta...

Prove the following identity: `cos^3thetas in3theta+sin^3thetacos3theta=3/4s in4thetadot`

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`Given,cos^3thetasin3theta+sin^3thetacos3theta`
using trigonometric identities and simplifying
=`(cos3theta+3costheta​)/4sin3theta+(3sintheta−sin3theta​)/4cos3theta`
=`1/4(sin3thetacos3theta+3costhetasin3theta+3sin3thetacostheta−sin3thetacos3theta)`
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