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1)

if  f(x) =x for x≤ 0

             =0 for x >0 , then f(x) at x=0 is


A) continuous but not differentiable

B) not continuous but differentiable

C) continuous and differentiable

D) not continuous and not differentiable

Answer:

Option A

Explanation:

 Given ,   

 f(x) =x for x≤ 0

         =0 for x >0 

for continuity at x=0

 LHS at x=0   lim

 \lim_{h \rightarrow 0^{-}}(0-h)=0 and RHL at x=0

 \lim_{x \rightarrow 0^{+}} f(x)= \lim_{x \rightarrow 0^{+}} 0=0

 Also, f(0)=0

 \therefore LHL=RHL=f(0)

 Hence, f(x) is continuous at x=0

 For differentiability at x=0

 f'(x)=1 for x ≤  0, 0 for x >0

 \therefore   f(x) is not differentiable at x=0