1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Infinite Limit Complex Function

  1. Jul 1, 2009 #1
    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.

  2. jcsd
  3. Jul 1, 2009 #2
    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.
  4. Jul 1, 2009 #3


    User Avatar
    Science Advisor
    Homework Helper

    z->infinity means |z|->infinity. What can you say about lim |8z^3+5z+2|?
  5. Jul 2, 2009 #4


    User Avatar
    Science Advisor

    Thanks, Dick. I was about to ask exactly what "z-> infinity" meant! In the complex plane there can be an infinite number of "infinities"!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook