Find limit.

I would agree 知足常樂 that the limit is not computable (or say undefined) as the function f(x) = sqrt(x-2) - sqrt(x-1) is not even defined at any negative values (its domain: [2,∞) ).

Remarks: f(x) is said to have a limit L as x approaches ܽa if and only if ݂f(x) can be
made arbitrarily close to L given that x is sufficiently close to ܽa. There is obviously not any points on the graph of f(x) = sqrt(x-2) - sqrt(x-1) that is sufficiently close to -inf. Therefore the limit does not exist.

If x is tends to +inf, the value of the limit = 0.

2015-05-03 09:30:22 補充：
The limit does not exist.

Actually I agree with you two (polarbearhmh and 知足常樂 ) that the answer should be undefined. But, the given answer is 0. I just wonder it is wrong.
Anyway, thank you so much!

2015-05-03 00:02:32 補充：
So, the answer should be "undefined" or "does not exist"?

undefined 吧

+inf 才可以

2015-04-30 13:48:03 補充：
√x is real if x is non-negative.

2015-05-02 19:22:49 補充：
You are welcome.

Then, I think that the given answer is wrong.

Or, the given question is wrong.
If it is +infinity, then no problem!

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