Arun Kumar12 Years agoHelloif f=x^alpha *sin(1/x) at x not equal to zero.thenby squeeze theorem limit x to 0 f will be = 0 for alpha > 0but randomness around 0 is too great for alpha=1 so not differentiable.so alpha > 1Thanks & RegardsArun KumarBtech, IIT DelhiAskiitians Faculty