Question

The equation of the tangent to the curve $y=x+\frac{4}{x^2},$ that is parallel to the $x-axis$, is

• A. $y=1$
• B. $y=2$
• C. $y=3$
• D. $y=0$

Answer 1

Answer: (C)

Parallel to x-axis $\Rightarrow \frac{dy}{dx}=0\Rightarrow 1-\frac{8}{x^3}=0$
$\Rightarrow x=2\Rightarrow y=3$
Equation of tangent is $y-3=0\left(x-2\right)\Rightarrow y-3=0$