Question

The derivative of $4\sqrt{x}-2$ is

• A. $\frac{1}{\sqrt{x}}$
• B. $2\sqrt{x}$
• C. $\frac{2}{\sqrt{x}}$
• D. $\sqrt{x}$

Answer 1

Answer: (C)

Let $y=4\sqrt{x}-2$
$\Rightarrow y=4x^{1/2}-2$
Differentiating y w.r.t. $x$, we get
$\frac{dy}{dx}=4\cdot \frac{1}{2}{x}^{\frac{1}{2}-1}-0$
$=2x^{-\frac{1}{2}}=\frac{2}{\sqrt{x}}$