The function f(x) = e|x| is
Given that, f(x) = e|x|
Let g(x) = |x| and h(x) = ex
Then, f(x) = hog(x)
We know that, modulus and exponential functions are continuous everywhere.
Since, composition of two continuous functions is a continuous function.
Hence, f(x) = hog(x) is continuous everywhere.
Now, v(x)=|x| is not differentiable at x=0.
Lv’(0) =
=
= (∵ v(x) = |x|)
=
=
=
Rv’(0) =
=
= (∵ v(x) = |x|)
=
=
=
⇒ Lv’ (0) ≠ Rv’(0)
⇒ |x| is not differentiable at x=0.
So, e|x| is not differentiable at x=0.
Hence, f(x) continuous everywhere but not differentiable at x = 0.