finding limits with square roots in function

Limits, differentiation, related rates, integration, trig integrals, etc.
trdert
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finding limits with square roots in function

Postby trdert » Wed Aug 05, 2009 8:47 pm

hi all,

i've got a couple problems i'm working on that require you to find the limit of a function with square roots. i'm having some issues with it. if anyone could lend a hand on the following problem it would be most appreciated:

limx->2 (sqrt(2x)-x)/(x-2)

i know i need to factor out x-2 but i don't know how to do that with the square root in the numerator.

thanks very much in advance!
tim

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stapel_eliz
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Postby stapel_eliz » Wed Aug 05, 2009 9:04 pm

This is an interesting one. I think they're expecting you to multiply by the conjugate of the numerator to get:

. . . . .

. . . . .

. . . . .

. . . . .

Can you see where to go from there? :wink:

trdert
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Re: finding limits with square roots in function

Postby trdert » Wed Aug 05, 2009 11:31 pm

fantastic, thanks! i'll review the whole multiplying by the conjugate thing also.

nona.m.nona
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Re: finding limits with square roots in function

Postby nona.m.nona » Thu Aug 06, 2009 11:47 am

The conjugate thing comes up a lot on tests so, yeh, make sure you know it. :wink:


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