Question

3 arctan n + arccot n= π​

Answer 1

Prove that, tan−1−1 4/3 + tan−1−1 12/5 = π - tan−1−1 56335633.

Solution:  

We know that tan−1−1 x + cot−1−1 x = π2π2

⇒ tan−1−1 x = π2π2 - cot−1−1 x

⇒ tan−1−1 4343  = π2π2 - cot−1−1 4343

and

tan−1−1 125125 = π2π2 - cot−1−1 125125

Now, L. H. S. = tan−1−1