Given,f(x)=∣x−1∣cos∣x−2∣sin∣x−1∣+(x−3)∣x2−5x+4∣
=∣x−1∣cos∣x−2∣sin∣x−1∣+(x−3)∣x−1∣∣x−4∣
=∣x−1∣[cos∣x−2∣sin∣x−1∣+(x−3)∣x−4∣]
We know that modulus function is not differentiable at values where modulus function is zero
So, we can say that function is non-differentiable at x=1 and x=4.