Find the limit by direct substitution.

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rowdy3
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Find the limit by direct substitution.

Postby rowdy3 » Wed May 05, 2010 3:23 am

Find the limit by direct substitution.

A. lim x-> 5
square root cubed of x^2 -2x - 23. I replaced all of the x's with 5 and got -2.

B. lim x-> -2
(4x^2 - 7x) / (6x + 10). I replaced all of the x's with -2 and got -15. Here's a link to the problem. It's 3A and 3B. Thanks.
http://pic20.picturetrail.com/VOL1370/5 ... 705398.jpg

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stapel_eliz
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Postby stapel_eliz » Wed May 05, 2010 1:19 pm

rowdy3 wrote:A. lim x-> 5
square root cubed of x^2 -2x - 23.

From what you have posted (in comparison with what the image shows), they appear to have missed teaching you a few topics back in algebra. The "square root, cubed, of [whatever]" is (sqrt[whatever])3. The exercise actually involves a cube root.

To learn about radicals (and you really need to know them, before calculus!!), try here.

Since the exercises require only that you evaluate the expressions (the "limit" concept isn't actually involved), I'm not sure what your question is...? If you are asking for confirmation of the calculator values, yes, the values are correct. :wink:


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