If $tan^{-1}\frac{n}{\pi} >\frac{\pi}{4}, $ n ∈ N, then the minimum value of n is
Answer & explanation
Correct answer: option 2
We have
$tan^{-1} \frac{n}{\pi} >\frac{\pi}{4}$
$ ⇒ tan^{-1}\frac{n}{\pi} > tan^{-1} 1 $ $[∵\frac{\pi}{4}= tan^{-1} 1]$
$ ⇒ tan\left(tan^{-1}\frac{n}{\pi}\right) > tan \left(tan^{-1} 1\right)$ [∵ tan θ is an increasing function]
$ ⇒ \frac{n}{\pi}> 1$ $[∵ tan(tan^{-1}x)=x]$
$ ⇒n > \pi ≅ 3.14 $
$ ⇒n = 4, 5, 6 ........$
Hence, the number value of n is 4.