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)

$y = 3$

Answer 2

Parallel to x-axis $\quad\Rightarrow \frac{dy}{dx} = 0\quad\Rightarrow1-\frac{8}{x^{3}} = 0$ $\Rightarrow x = 2\quad\Rightarrow y = 3$ Equation of tangent is $y - 3 = 0\left(x - 2\right)\quad\Rightarrow y - 3 = 0$