Question
( tan ^{-1}(a)+tan ^{-1}(b)=tan ^{-1}left(frac{a+b}{1-a b}right) )
( begin{aligned} therefore tan ^{-1}(1)+tan ^{-1}(2)=& tan ^{-1}left(frac{1+2}{1-(1)(2)}right)=tan ^{-1}(-3) =& 11-tan ^{-1}(3) end{aligned} )
( pi-tan ^{-1}(3)+tan ^{-1}(3)=frac{11}{11} )
( operatorname{ard} tan ^{-1}left(frac{1}{2}right)+tan ^{-1}left(frac{1}{3}right)=tan ^{-1}left(frac{1 / 2+1 / 3}{1-frac{1}{2}left(frac{1}{3}right)}right) )
( =tan ^{-1}left(frac{5 / 6}{5 / 6}right)=tan ^{-1}(1) )
(0.2)( : 2left(tan ^{-1}(1)+tan ^{-1}(1)right)=2(184+pi u)=pi )
( 12+ )
Hurce proved.

OVCU 2 Call 8 4 IV. Show that tan-11 + tan-+ 2 + tan* 3 = 2(tan-11 + tan-1+tan-1)
Solution
