Q. If $\tan^{- 1}{\left( \frac{1}{3} \right) + \tan^{- 1}{\left( \frac{3}{4} \right) - \tan^{- 1}{\left( \frac{x}{3} \right) = 0}}}$, then $x$ is equal to

A) $\frac{7}{3}$
B) 3
C) $\frac{11}{3}$
D) $\frac{13}{3}$
Explanation

(d)
Given, $\tan^{- 1}{\left( \frac{1}{3} \right) + \tan^{- 1}\left( \frac{3}{4} \right)} = \tan^{- 1}\left( \frac{x}{3} \right)$
$\Rightarrow \ \tan^{- 1}\left( \frac{\frac{1}{3} + \frac{3}{4}}{1 - \frac{1}{3} \times \frac{3}{4}} \right) = \tan^{- 1}\left( \frac{x}{3} \right)$
$\Rightarrow \ \frac{13}{9} = \frac{x}{3}\ \ \Rightarrow \ \ x = \frac{13}{3}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.