Verify Rolle’s theorem for each of the following functions:


Condition (1):


Since, f(x)=(x-1)(x-2)2 is a polynomial and we know every polynomial function is continuous for all xϵR.


f(x)= (x-1)(x-2)2 is continuous on [1,2].


Condition (2):


Here, f’(x)= (x-2)2+2(x-1)(x-2) which exist in [1,2].


So, f(x)= (x-1)(x-2)2 is differentiable on (1,2).


Condition (3):


Here, f(1)= (1-1)(1-2)2=0


And f(2)= (2-1)(2-2)2=0


i.e. f(1)=f(2)


Conditions of Rolle’s theorem are satisfied.


Hence, there exist at least one cϵ(1,2) such that f’(c)=0


i.e. (c-2)2+2(c-1)(c-2)=0


(3c-4)(c-2)=0


i.e. c=2 or c=4÷3


Value of


Thus, Rolle’s theorem is satisfied.


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