Differential Equations Question 95
Question: $ y=4\sin 3x $ is a solution of the differential equation
[AI CBSE 1986]
Options:
A) $ \frac{dy}{dx}+8y=0 $
B) $ \frac{dy}{dx}-8y=0 $
C) $ \frac{d^{2}y}{dx^{2}}+9y=0 $
D) $ \frac{d^{2}y}{dx^{2}}-9y=0 $
Show Answer
Answer:
Correct Answer: C
Solution:
Let $ y=4\sin 3x\Rightarrow \frac{dy}{dx}=12\cos 3x $
Therefore $ \frac{d^{2}y}{dx^{2}}=-36\sin 3x=-9\times 4\sin 3x=-9y $
Therefore $ \frac{d^{2}y}{dx^{2}}+9y=0 $ .
BETA
