Question

If $t = \sqrt{x} + 4$, then $\left.\frac{dx}{dt}\right|_{t=4}$ is

• A. 4
• B. 0
• C. 8
• D. 16

Answer 1

Answer: (B)

0

Answer 2

$x = (t – 4)^2$
$\frac{dx}{dt} = 2t - 8$
For $t=0$
$\frac{dx}{dt} = 2x^4 - 8$
$\frac{dx}{dt} = 0$
So, the correct option is (B): 0.