# Toronto Math Forum

## MAT334-2018F => MAT334--Lectures & Home Assignments => Topic started by: wentao huang on November 15, 2018, 01:39:45 AM

Title: 2.5 Q 28
Post by: wentao huang on November 15, 2018, 01:39:45 AM
I think I know how to prove essential part, by the definition provided by textbook. A singularity point is essential when it is neither equal to infinity or bounded. Hence, it is equivalent to say that limit does not exist at that singularity point because left side limit and right side limit are different. But for analytic part, I try to solve it by Riemann Cauchy equation, but the function itself is very complicated by separating u and z to a+bi and x+yi.
Hence, I wonder if we can have a better way to prove analytic part or I just need to keep calculating.
Title: Re: 2.5 Q 28
Post by: Victor Ivrii on November 15, 2018, 06:14:47 AM
Quote
point because left side limit and right side limit are different
There is no "left / right side limit" in complex variables. Statement like this will bring you 0 mark for the whole problem in the exam paper.