# Find the points where the function is not differentiable

by zorro
Tags: differentiable, function, points
 P: 1,394 1. The problem statement, all variables and given/known data Find the points where the function given by $f(x)=&space;\left&space;(&space;x^{2}-1&space;\right&space;)\left&space;|&space;x^{2}-3x+2&space;\right&space;|+cos\left&space;|&space;x&space;\right&space;|$ is not differentiable. 3. The attempt at a solution I got the doubtful points as +-1, 2 How do I check the differentiability now? The mod. function is confusing me a bit.