IIT-JEE 1983Question 1
The value of $\tan\left[\cos^{-1}\left(\dfrac45\right)+\tan^{-1}\left(\dfrac23\right)\right]$ is
Inverse Trigonometric Functions
Solution
$\cos^{-1}\frac45=\tan^{-1}\frac34$; $\tan\left(\tan^{-1}\frac34+\tan^{-1}\frac23\right)=\frac{\frac{17}{12}}{\frac12}=\frac{17}6$, not among the listed values.