Engineering
Mathematics
Important Points on Derivability
Question

Consider the function, f(x) = | x – 2 | + | x – 5 |, x ∈ R.

Statement 1 : f '(3) = 0

Statement 2 : f is continuous in [2, 5], differentiable in (2, 5) and f(2) = f(5).

Statement 1 is true, Statement 2 is false.

Statement 1 is false, Statement 2 is true.

Statement 1 is true, Statement 2 is true, Statement 2 is a correct explanation for Statement 1.

Statement 1 is true, Statement 2 is true, Statement 2 is not a correct explanation for Statement 2.

JEE Advance
College PredictorLive

Know your College Admission Chances Based on your Rank/Percentile, Category and Home State.

Get your JEE Main Personalised Report with Top Predicted Colleges in JoSA

Solution

f(x) = | x – 2 | + | x – 5 | , x ∈ R

 f(x)={2x+7,                   x<23,2x52x7,x>5

It is clear that f(x) is continuous in R and

(,2)(2,5)(5,)

Statement 2 is correct.

Statement 1 is also correct but Statement 2 is not the correct explanation of Statement 1.