Limits Continuity And Differentiability Question 53

Question: If $ s=\sqrt{t^{2}+1} $ , then $ \frac{d^{2}s}{dt^{2}} $ is equal to

Options:

A) $ \frac{1}{s} $

B) $ \frac{1}{s^{2}} $

C) $ \frac{1}{s^{3}} $

D) $ \frac{1}{s^{4}} $

Show Answer

Answer:

Correct Answer: C

Solution:

$ s=\sqrt{t^{2}+1} $

$ \Rightarrow \frac{ds}{dt}=\frac{t}{\sqrt{t^{2}+1}}\Rightarrow \frac{d^{2}s}{dt^{2}}=\frac{1}{\sqrt{{{( t^{2}+1 )}^{3}}}} $

$ \Rightarrow \frac{d^{2}s}{dt^{2}}=\frac{1}{s^{3}} $