(c) Given that, $\tan^{- 1}{x - \tan^{- 1}{y = \tan^{- 1}A}}$ $\Rightarrow \tan^{- 1}{\left( \frac{x - y}{1 + xy} \right) = \tan^{- 1}A}$ Hence, $A = \frac{x - y}{1 + xy}$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.