Question

If $y=A\sin 5x$, then $\frac{d^{2}y}{{dx}^2}=$

• A. $-25y$
• B. $25y$
• C. $5y$
• D. $-5y$

Answer 1

The correct option is A $-25y$

Differentiate $y=A\sin 5x$ with respect to $x$,

$\frac{dy}{dx}=5A\cos 5x$

Again differentiate above equation with respect to $x$,

$\frac{d^{2}y}{d{x}^2}=-25A\sin 5x$

$=-25y$