Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

For the curve $x=t^2-1, y=t^2-t$, the tangent line is perpendicular to x - axis when

Options:

$t=0$

$t=\infty$

$t=1 / \sqrt{3}$

$t=-1 / \sqrt{3}$

Correct Answer:

$t=0$

Explanation:

We have,

$x=t^2-1, y=t^2-t$

∴  $\frac{d y}{d x}=\frac{\frac{d y}{d t}}{\frac{d x}{d t}}=\frac{2 t-1}{2 t}$

If the tangent is perpendicular to x - axis, then

$\frac{d x}{d y}=0 \Rightarrow \frac{2 t}{2 t-1}=0 \Rightarrow t=0$