If $g(x)=∫\frac{dx}{x^{\frac{1}{2}}+x^{\frac{1}{6}}}$, then $g(1) - g(0)$ is: |
$4-\frac{3π}{2}$ $5-6log_e2$ $5+6log_e2$ $\frac{3π}{2}-4$ |
$\frac{3π}{2}-4$ |
The correct answer is Option (4) → $\frac{3π}{2}-4$ $g(x)=∫\frac{dx}{x^{\frac{1}{2}}+x^{\frac{1}{6}}}$ $=∫\frac{dx}{x^{\frac{1}{6}}(x^{\frac{1}{3}}+1)}$ let $t=x^{\frac{1}{3}}$ $⇒x=t^3$ and $x^{\frac{1}{6}}=t^{\frac{1}{2}}$ Now, $dx=3t^2dt$ Substituting this, $g(x)=\int\frac{3t^2dt}{t^{\frac{1}{2}}(t+1)}dt$ $=3\int\left(t^{\frac{1}{2}}-\frac{t^{\frac{1}{2}}}{t+1}\right)dt$ $=2t^{\frac{3}{2}}-3.\left(2\sqrt{t}-2\tan^{-1}(\sqrt{t})\right)+C$ $=2x^{\frac{1}{2}}-6x^{\frac{1}{6}}+6\tan^{-1}(x^{\frac{1}{6}})+C$ $∴g(1)-g(0)=\left[-4+\frac{3π}{2}+C-0\right]=\frac{3π}{2}-4$ |