Differentiation Question 40

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

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:

[c] $ y=1+x+\frac{x^{2}}{2!}+\frac{x^{3}}{3!}+…+\frac{x^{n}}{n!} $ Or $ \frac{dy}{dx}=0+1+x+\frac{x^{2}}{2!}+…+\frac{{x^{n-1}}}{(n-1)!} $ Or $ \frac{dy}{dx}+\frac{x^{n}}{n!}=1+x+\frac{x^{2}}{2!}+…+\frac{x^{n}}{n!} $ Or $ \frac{dy}{dx}=y-\frac{x^{n}}{n!} $