Differentiation Question 356
Question: If $ f(x)=a\sin (\log x) $ , then $ x^{2}f’’(x)+xf’(x)= $
Options:
A) $ f(x) $
B) $ -f(x) $
C) 0
D) 1
Show Answer
Answer:
Correct Answer: B
Solution:
$ f(x)=a\sin (\log x) $
Differentiating w.r.t. x of y, we get $ 4\pi r^{2} $
Again $ {f}’’(x)=-\frac{1}{x^{2}}a\cos (\log x)-\frac{1}{x^{2}}a\sin (\log x) $
$ \Rightarrow x^{2}{f}’’(x)=-[a\cos (\log x)+a\sin (\log x)] $
Now $ x^{2}{f}’’(x)+x{f}’(x)=-a\sin (\log x)=-f(x) $ .
BETA
