Question

If $y=2^{-x}$, then $\frac{dy}{dx}$ is equal to :

• A. $-\frac{x}{2^{x+1}}$
• B. $2^x\log 2$
• C. $2^{-x}\log 2$
• D. $\frac{\log \frac{1}{2}}{2^x}$

Answer 1

Answer: (D)

Let $y=2^{-x}$
$\frac{dy}{dx}=\frac{2^{-x}}{\log 2}\left(-1\right)=\frac{-1}{2^x\log 2}\frac{\log \frac{1}{2}}{2^x}$