Prove that `cot(pi/4-2cot^(- 1)3)=7`

Explanation

We have to proof that `cot(pi/4-2cot^(- 1)3)=7`

let `2cot^(−1)3=theta`

` cot^(−1)3=theta/2`

`cottheta/2=3`

`tantheta/2=1/3`

`⇒cot((pi/4)-theta)=7`

`⇒(cot(pi/4)cottheta+1)/(cottheta-cot(pi/4))=7`

`⇒(cottheta+1)/(cottheta-1)=7`

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