Differentiation Question 69

Question: $ \frac{d}{dx}( x^{2}\sin \frac{1}{x} )= $

Options:

A) $ \cos ( \frac{1}{x} )+2x\sin ( \frac{1}{x} ) $

B) $ 2x\sin ( \frac{1}{x} )-\cos ( \frac{1}{x} ) $

C) $ \cos ( \frac{1}{x} )-2x\sin ( \frac{1}{x} ) $

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

$ \frac{d}{dx}( x^{2}\sin \frac{1}{x} )=x^{2}\cos ( \frac{1}{x} )\frac{d}{dx}( \frac{1}{x} ) $

$ +2x\sin ( \frac{1}{x} ) $

$ =-\frac{1}{x^{2}}.x^{2}\cos ( \frac{1}{x} )+2x\sin ( \frac{1}{x} )=2x\sin ( \frac{1}{x} )-\cos ( \frac{1}{x} ) $ .