Question

If $y=a{x}^2+b$, then $\frac{dy}{dx}$ at $x=2$ is equal to

• A. $4a$
• B. $3a$
• C. $2a$
• D. none of these

Answer 1

Answer: (A)

We have, $y=a{x}^2+b$
$\Rightarrow \frac{dy}{dx}=2ax$
$\frac{dy}{dx}{|}_{x=2}=2a\times 2=4a$