Differentiation Question 221

Question: If $ y=1+x+\frac{x^{2}}{2!}+\frac{x^{3}}{3!}+…..+\frac{x^{n}}{n!} $ , then $ \frac{dy}{dx}= $

Options:

A) y

B) $ y+\frac{x^{n}}{n!} $

C) $ y-\frac{x^{n}}{n!} $

D) $ y-1-\frac{x^{n}}{n!} $

Show Answer

Answer:

Correct Answer: C

Solution:

$ y=1+x+\frac{x^{2}}{2!}+\frac{x^{3}}{3!}+….+\frac{x^{n}}{n!} $

Therefore $ [ (\log \tan x+1)+\frac{1}{\tan x\log \tan x} ] $

Therefore $ \frac{dy}{dx}+\frac{x^{n}}{n!}=1+x+\frac{x^{2}}{2!}+…..+\frac{x^{n}}{n!} $

Therefore $ \frac{dy}{dx}=y-\frac{x^{n}}{n!} $ .