State True or False for the statements
Rolle’s theorem is applicable for the function f(x) = |x – 1| in [0, 2].

Question

State True or False for the statements Rolle’s theorem is applicable for the function f(x) = |x – 1| in [0, 2].

Philoid · Accepted Answer

False

Rolle’s Theorem states that, Let f : [a, b] → R be continuous on [a, b] and differentiable on (a, b), such that f(a) = f(b), where a and b are some real numbers.Then there exists some c in (a, b) such that f’(c) = 0.

We have, f(x) = |x – 1| in [0, 2].

Since, polynomial and modulus functions are continuous everywhere f(x) is continuous.

Now, x-1=0

⇒ x=1

We need to check if f(x) is differentiable at x=1 or not.

We have,

Lf’(1) =

=

= (∵ f(x) = 1-x, if x< 1)

=

Rf’(1) =

=

= (∵ f(x) = x-1, if 1< x)

=

⇒ Lf’(1) ≠ Rf’(1)

⇒ f(x) is not differentiable at x=1.

Hence, rolle’s theorem is not applicable on f(x) since it is not differentiable at x=1 ∈ (0,2).

State True or False for the statementsRolle’s theorem is applicable for the function f(x) = |x – 1| in [0, 2].

State True or False for the statements
Rolle’s theorem is applicable for the function f(x) = |x – 1| in [0, 2].