Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

The equation of the normal to the curve y = x(2 - x) at the point (2, 0) is

Options:

x - 2y = 2

x - 2y + 2 = 0

2x + y = 4

2x + y - 4 = 0

Correct Answer:

x - 2y = 2

Explanation:

The equation of the curve is

$y=x(2-x)$ or, $y=2 x-x^2$

$\Rightarrow \frac{d y}{d x}=2-2 x \Rightarrow\left(\frac{d y}{d x}\right)_{(2,0)}=2-2 \times 2=-2$

So, the equation of the normal at (2, 0) is

$y-0=-\frac{1}{-2}(x-2)$  or,  $2 y=x-2$