points of non differentiability

vijay kharya

the points where the function defined by |x^2-3x+2|+cos|x| is not differentiable, where |x| represents modulus function,

A) 1,2

b) 0,1,2

c) 0

d) 0,1

e) 0,2

Aakash Krishnan

option c is crt bcoz

after differentiating the only value satisfying f(x) and f'(x) is zero

hence option c is crt

vijay kharya

f(x) is not differentiable is what i have typed check and then reply ur answer is wrong!!!!!!

Aakash Krishnan

whooops sry the only option left other than zero is a option

is it crt??

vijay kharya

yes , ur correect but plz. explain why is function differentiable at x=0, any clue??, i couldn't get ur reply, and how have u differentiated at x=0 without checking differentiability???

Aakash Krishnan

after derivatives u find that both functions are continuous....

ans is 3

so if functions are continuous we can check they are differentiable or not.....they are not differentiable

only zero makes it possible ur hint was they are not diff

so the only option left other than zero is option a hence....

vijay kharya

zero makes what differentiable????, anyway after reading the question now so many times , i've realized that since cos is an even function and and so there will be no effect of mod on cos|x| in the vicinity of zero, so function is differentiable at zero,i think that this thing can be further generalised that if f(x) is an even function then f( |x|) is differentiable at x=0.

Ask & Discuss Questions with Community & Experts