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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: suskieanna on March 20, 2019, 11:24:47 am

Title: Adding Cis??
Post by: suskieanna on March 20, 2019, 11:24:47 am
Hello I have a simple question to ask!

Is Cis[0] + Cis
Title: Re: Adding Cis??
Post by: AlphaZero on March 20, 2019, 11:50:54 am
Quote from: suskieanna on March 20, 2019, 11:24:47 am
Hello I have a simple question to ask!

Is Cis[0] + Cis
  • = Cis[0+x] = Cis
  • ??

In general,  \(\text{cis}(a)+\text{cis}(b)\neq \text{cis}(a+b)\).

This is pretty easy to see using  \(\text{cis}(\theta)=\cos(\theta)+i\sin(\theta)\).
Side note:  it is true however that  \(\text{cis}(a)\text{cis}(b)=\text{cis}(a+b)\).