limit again

if f(x)= sin-1([x]+x)/[x] ,[x]≠0
= 0 ,[x]=0

then find lim f(x)
x→0

8 Answers

1357
Manish Shankar ·

does not exist

f(0+)=0
f(0-)=pi/2

if I m right

1
champ ·

can i get a detailed answer?

106
Asish Mahapatra ·

manish sir: how f(0+) = 0? it is undefined for 1>x≥0 isnt it?

ive a doubt. Take this case here the function has domain (-∞,0)U[1,∞)
So here lim(x→0) will exist or not??

In many cases ive seen that the limit is taken as f(0-) in this case as the function itself is not defined at RHL(as we do while checking if a function is continuous). While in other cases the answer is given as lim does not exist bcz RHL is not defined

1357
Manish Shankar ·

Here I also initially thought the same

but here f(x)=0 for [x]=0 that means x in [0,1)

106
Asish Mahapatra ·

oh yeah!!! i thot it was x=0.

anyways what abt the dbt in my last para? wud we say limit does not exist? if it was given x=0 instead of [x]=0 ??

1
aieeee ·

then,it couldn't hav been defined

106
Asish Mahapatra ·

the value wud not have been defined. but im asking abt limit. I guess that since we had discussed this and got no satisfactory conclusion we shud wait for others... please wait abhisek b4 answering

1
b_k_dubey ·

LHL=\lim_{h\rightarrow 0}f(0-h)=\frac{sin^{-1}([-h]-h)}{-[h]}=\frac{sin^{-1}(-1-h)}{-1}=\frac{\pi }{2}

RHL=\lim_{h\rightarrow 0}f(0+h)=0

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