Differentiation Question 237

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

[Karnataka CET 1999]

Options:

A) y

B) $ y-1 $

C) $ y+1 $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

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

Therefore $ y=e^{x} $

Differentiating with respect to x, we get $ \frac{dy}{dx}=e^{x}=y $ .