Discuss the applicability of Rolle’s theorem for the following functions on the indicated intervals :

f(x) = 2x2 – 5x + 3 on [1, 3]

Given function is:


f(x) = 2x2 – 5x + 3 on [1,3]


Since given function ‘f’ is a polynomial. So, it is continuous and differentiable every where.


Now, we find the values of function at the extremum values.


f(1) = 2(1)2–5(1) + 3


f(1) = 2 – 5 + 3


f(1) = 0 ......(1)


f(3) = 2(3)2–5(3) + 3


f(3) = 2(9)–15 + 3


f(3) = 18 – 12


f(3) = 6 ......(2)


From (1) and (2), we can say that,


f(1)≠f(3)


Rolle’s theorem is not applicable for the function f in interval [1,3].


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