Is f(x)=(1-e^x)/(1-x^2) increasing or decreasing at x=2?

1 Answer
Jun 28, 2016

the first derivative is negative. The function is decreasing.

Explanation:

The first derivative of f is ((1-x^2)(-e^x) -(1-e^x)(-2x))/(1-x^2)^2
its sign is the same as the sign of its numerator which is
3e^2 + 4 (1-e^2) = -e^2 + 4 <0

It is negative thus the function is decreasing at x=2

graph{(1-e^x)/(1-x^2) [-10, 10, -5, 5]}