Question

The derivative of $f(x)=3|2+x|$ at the point $x_0=-3$ is

• A. $3$
• B. $-3$
• C. $0$
• D. None of the above

Answer 1

Answer: (B)

We have, $f(x)=3|2+x|$
as $f(x)=|x|\Rightarrow f^{\prime }(x)=\frac{x}{|x|}$
Now, $f(x)=3|x+2|$
$\Rightarrow f(x)=3\frac{x+2}{|x+2|}=-3($ as $x_0=-3)$