Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

The point on the curve y2 = x, the tangent at which makes an angle of 45° with x-axis will be given by

Options:

$\left(\frac{1}{2}, \frac{1}{4}\right)$

$\left(\frac{1}{2}, \frac{1}{2}\right)$

(2, 2)

$\left(\frac{1}{4}, \frac{1}{2}\right)$

Correct Answer:

$\left(\frac{1}{4}, \frac{1}{2}\right)$

Explanation:

$y^2=x \Rightarrow 2 y \frac{d y}{d x}=1$

$\Rightarrow \frac{d y}{d x}=\frac{1}{2 y}=\tan 45°=1$  (given)

$\Rightarrow y=\frac{1}{2}$      ∴  $x=\frac{1}{4}$

∴  Point is $\left(\frac{1}{4}, \frac{1}{2}\right)$.