Question

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

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

Answer 1

The correct option is D $y=3$

Given tangent is parallel to x axis

so slope is 0

$\frac{dy}{dx}=0$

$1-\frac{8}{x^3}=0$

$x=2$

therefore at $x=2$ $y=3$

equation of tangent is $y=3$