- #1

- 5

- 0

lim square root of u^4+3u+6

u->-2

Evaluate the limit

lim x^2+5x+4/x^2-3x-4

x->-4

Find the limit

lim t^2+2/t^3+t^2-1

t->-infinity

Please can someone help me?

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- Thread starter bballj228
- Start date

- #1

- 5

- 0

lim square root of u^4+3u+6

u->-2

Evaluate the limit

lim x^2+5x+4/x^2-3x-4

x->-4

Find the limit

lim t^2+2/t^3+t^2-1

t->-infinity

Please can someone help me?

Edit/Delete Message

- #2

arildno

Science Advisor

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Gold Member

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Thus, we may check whether 16 is, indeed, the limit as u tends to -2.

We therefore manipulate the expression:

[tex]|u^{4}+3u+6-16|=|(u^{4}-2^{4}+3(u+2)|=|(u^{2}+2^{2})(u-2)(u+2)+3(u+2)|=|u+2||(u^{2}+4)(u-2)|[/tex].

Thus, if you can argue for that the latter factor is bounded as u tends to -2, the factor |u+2| will ensure that the entire expression tends to zero, proving that 16, indeed, is the limit of the given expression.

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