Question

( quad tan ^{-1} A+tan ^{-1} B=tan ^{-1} frac{A+B}{1-A B} )
Then ( tan ^{-1} 2 x+tan ^{-1} 3 x=tan frac{2 x+3 x}{1-2 x cdot 3 x}=pi / 4 )
( Rightarrow frac{5 x}{1-6 x^{2}}=tan pi=1 )
thenee have folo roots.

# 15. The number of roots of the equation tan-1 2x + tan-13x = (a) o (b) 1 (d) infinite (c) 2

Solution