question_answer 1)

Prove that f(x) = [x], 0 < x < 3 is not derivable at x = 1. Also check its differentiability at x = 2. 

Answer:

At x = 1       L.H.D.                         Since L.H.D. does not exist therefore f is not derivable at x =1.       At x = 2       L.H.D.             Since LHD does not exist. Therefore f is not derivable at x =2. Hence the result.