1.

If, \(y=\sqrt x+\frac{1}{\sqrt x}\) prove that :-  \(2x.\frac{dy}{dx}+y=2\sqrt x.\)

Answer»

Given,

\(y=\sqrt x+\frac{1}{\sqrt{x}}\)

⇒ \(\frac{dy}{dx}=\frac{d}{dx}(\sqrt x+\frac{1}{\sqrt x})\) 

\(=\frac{1}{2}x^\frac{1}{2}+(-\frac{1}{2})x^\frac{-3}{2}\)

\(=\frac{1}{2}.\frac{1}{\sqrt{x}}-\frac{1}{2x\sqrt{x}}\)

∴ L.H.S 

= \(2x\frac{dy}{dx}+y\) 

\(=2x(\frac{1}{2x\sqrt x}-\frac{1}{2x\sqrt x})+\sqrt{x}+\frac{1}{\sqrt{x}}\)  

\(=\sqrt{x}-\frac{1}{\sqrt{x}}+\sqrt{x}+\frac{1}{\sqrt{x}}\) 

\(=2\sqrt{x}\) 

= R.H.S



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