Question

3. What is derivative of |x – 3| at x = – 1. 4. What are the points of discontinuity of f(x)= { (x-1)+(x+1)}/{(x-7)(x-6)} 5. Write the number of points of discontinuity of f(x) = [x] in [3, 7].

Answer 1

x-3  at x= -1.4 = -4.4
:. |x-3|= - x+3 
diff (3-x) w.r.t. x = -1  (Ans)

Pt. of discontinuity of {(x-1)+(x+1)}/{(x-7)(x-6)}5 is x=7; x=6

No. of pt. of discontinuity for f(x)=[x] in [3,7] is 4     {4,5,6,7}