Prove that: `tan4theta=(4t a ntheta(1-tan^2theta))/(1-6tan^2theta+tan^4theta)`

Explanation

`tan 4 theta=frac{4 tan theta-4 tan ^{3} theta}{1-6 tan ^{2} theta+tan ^{4} theta}`

Explanation:

Using the identity `tan 2 theta=frac{2 tan theta}{1-tan ^{2} theta}`

`tan 4 theta=frac{2 tan 2 theta}{1-tan ^{2}(2 theta)}`


`=frac{2 times frac{2 tan theta}{1-tan ^{2} theta}}{1-(frac{2 tan theta}{1-tan ^{2} theta})^{2}}`



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