Integral Calculus Question 301

Question: $ \int_{{}}^{{}}{\frac{\log (x+\sqrt{1+x^{2}})}{\sqrt{1+x^{2}}}\ dx=} $

Options:

A) $ \frac{1}{2}{{[\log (x+\sqrt{1+x^{2}})]}^{2}}+c $

B) $ \log {{(x+\sqrt{1+x^{2}})}^{2}}+c $

C) $ \log (x+\sqrt{1+x^{2}})+c $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

Put $ \log (x+\sqrt{1+x^{2}})=t\Rightarrow \frac{1}{\sqrt{1+x^{2}}},dx=dt, $ then $ \int_{{}}^{{}}{\frac{\log (x+\sqrt{1+x^{2}})}{\sqrt{1+x^{2}}},dx}=\int_{{}}^{{}}{t,dt} $ $ =\frac{1}{2}{{[ \log (x+\sqrt{1+x^{2}}) ]}^{2}}+c $ .