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JG89
Mar20-09, 04:56 PM
If f is continuous in some neighborhood of x = a, then is the following true:

\lim_{x \rightarrow a} f(x) = f( \lim_{x \rightarrow a} x) ?

de_brook
Mar20-09, 05:23 PM
If f is continuous in some neighborhood of x = a, it is also continuous at x = a, because x = a is contained in the neighborhood. The l.h.s equals the r.h.s because of the fact that the limit as x tends to 'a' of f(x) equals 'f(a)' (because of continuity of f) and on the other hand, f of the limit of x as 'x tends to a' is obviously f(a) since lim(x) = a as x --> a

poutsos.A
Mar20-09, 08:59 PM
If f is continuous in some neighborhood of x = a, then is the following true:

\lim_{x \rightarrow a} f(x) = f( \lim_{x \rightarrow a} x) ?

This an anorthodoxe way of writting : f is continuous at x=a <====>
\lim_{x \rightarrow a} f(x)=f(a)

But i suppose is correct since \lim_{x\rightarrow a}x = a

lurflurf
Mar21-09, 01:13 AM
If f is continuous in some neighborhood of x = a, then is the following true:

\lim_{x \rightarrow a} f(x) = f( \lim_{x \rightarrow a} x) ?

That is true. This makes clear the idea of continuity.