Author Topic: TUT5101 QUIZ2  (Read 879 times)

Yiheng Bian

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TUT5101 QUIZ2
« on: January 30, 2020, 12:42:13 AM »
Question:
$$
h(z)=\frac{Log(z)}{z}
$$
We know when
$$
 z \rightarrow \infty
$$
$$
Log(z) \rightarrow \infty
$$
So we can use L'Hopital rules and get
$$
\frac{1}{z}
$$
So
$$
\text{limit is zero}
$$


Victor Ivrii

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Re: TUT5101 QUIZ2
« Reply #1 on: January 30, 2020, 06:39:52 AM »
Wrong reasoning

Yiheng Bian

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Re: TUT5101 QUIZ2
« Reply #2 on: January 30, 2020, 09:25:16 PM »
Sorry sir, , could you point it out?

Victor Ivrii

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Re: TUT5101 QUIZ2
« Reply #3 on: January 31, 2020, 09:05:11 AM »
You cannot use LH out of the box for complex variables. You need to consider $z=re^{i\theta}$ and consider $\bigl|\dfrac{\operatorname{Log}(z)}{z}\bigr|$ ...

Yiheng Bian

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Re: TUT5101 QUIZ2
« Reply #4 on: January 31, 2020, 11:31:11 PM »
Ok, I got it. Thank you sir