(i) Show that tan−1 \(\frac{1}{5}\) + tan−1\(\frac{1}{7}\) + tan−1\(\frac{1}{3}\) + tan−1\(\frac{1}{8}\) = \(\frac{π}{4}\)
(ii) Given that Cot 3θ = \(\frac{3cot^2 θ -1}{cot^3 θ - 3cot θ'}\)
cot-1 \(\frac{3x^2 θ -1}{x^3 θ - 3x θ'}\) , |x|<√3 is 3cot1 x