Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Linear Programming

Question:

The point at which the tangent to the curve $y=\sqrt{4x-3}-1$ has its slope $\frac{2}{3}$, is :

Options:

(3, 2)

(1, 3)

(2, 2)

(2, 3)

Correct Answer:

(3, 2)

Explanation:

The correct answer is Option (1) → (3, 2)

$y=\sqrt{4x-3}-1$  ...(1)

so $(y+1)^2=4x-3$ ....(2)

differentiating wrt x

$2(y+1)\frac{dy}{dx}=4$ so $\frac{dy}{dx}=\frac{2}{3}$

so $2(y+1)\frac{2}{3}=4⇒y=2$

From (2) → $9=4x-3$

$⇒x=3$

Point (3, 2)