$f(x)=\ln x, g(x)=\left(x+\sqrt{1+x^{2}}\right)$

$y=\sqrt{\cos 2 x}$ হলে, $\left(y y_{1}\right)^{2}= ?$

দৃশ্যকল্প: $\mathrm{ f(x, y)=\sqrt{x}+\sqrt{y}-\sqrt{2}}, \mathrm{t=2 \sin ^{-1} x}$.

$\mathrm{y}=\mathrm{e}^{\operatorname{\theta g}(\mathrm{x})}$ এবং $\mathrm{f}(\mathrm{x})=\frac{1}{\mathrm{x}}$