Question

The abscissa of the point , where the tangent to the curve

y² = 4a {(x + a sin (x/a)} is parallel to x-axis is –

• A. 1
• B. –1
• C. ap
• D. None of these

Answer 1

Answer: (C)

ap

Answer 2

2y $\frac{dy}{dx}$ = 4a (1 + cos $\frac{x}{a}$)

̃ $\frac{dy}{dx}$ = $\frac{4a\left( 1 + \cos\frac{x}{a} \right)}{2y}$= 0

̃ 1 +cos $\frac{x}{a}$= 0 ̃ x = ap