Let f(x) = |sinx|. Then
Given that, f(x) = |sinx|
Let g(x) = sinx and h(x) = |x|
Then, f(x) = hog(x)
We know that, modulus function and sine function 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.
⇒ h(x) is not differentiable at x=0.
So, f(x) is not differentiable where sinx = 0
We know that sinx=0 at x = nπ, n ∈ Z
Hence, f(x) is everywhere continuous but not differentiable x = nπ, n ∈ Z