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Infinite Limit Complex Function

by rmcclurk
Tags: complex, function, infinite, limit
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Jul1-09, 05:13 PM
P: 4
1. The problem statement, all variables and given/known data
Find the limit of a complex number involving infinity.

2. Relevant equations
Lim z->infiity of (8z^3+5z+2)

3. The attempt at a solution
I tried to split the problem into real and imaginary parts using z = x+iy, but I don't know how to deal with the z->infinity.

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Jul1-09, 08:04 PM
P: 675
I could be misreading the problem, but the real part and imaginary part of that equation will go to infinity as well no matter which you take.
Jul1-09, 08:37 PM
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P: 25,251
z->infinity means |z|->infinity. What can you say about lim |8z^3+5z+2|?

Jul2-09, 05:37 AM
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P: 39,293
Infinite Limit Complex Function

Thanks, Dick. I was about to ask exactly what "z-> infinity" meant! In the complex plane there can be an infinite number of "infinities"!

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