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I need help with number 2 and can you please do it the same way as the paper so I can understand it better.

I need help with number 2 and can you please do it the same way as the paper so I-example-1
User Daddygames
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1 Answer

6 votes

ANSWER:

The cosine and sine values are reversed.


4\cdot cis\mleft((\pi)/(3)\mright)=2+2\sqrt[]{3i}

Explanation:

We can rewrite the function as follows:


a\cdot cis(\theta)=a\cdot\cos (\theta)+ai\cdot\sin \theta

In this case, then it would be:


\begin{gathered} 4\cdot cis\mleft((\pi)/(3)\mright)=4\cdot\cos \mleft((\pi)/(3)\mright)+4i\cdot\sin \mleft((\pi)/(3)\mright) \\ \cos \mleft((\pi)/(3)\mright)=(1)/(2) \\ \sin \mleft((\pi)/(3)\mright)=\frac{\sqrt[]{3}}{2} \\ \text{ replacing} \\ 4\cdot cis\mleft((\pi)/(3)\mright)=4\cdot(1)/(2)+4i\cdot\frac{\sqrt[]{3}}{2} \\ 4\cdot cis\mleft((\pi)/(3)\mright)=2+2\sqrt[]{3i} \end{gathered}

What it means is that the error was that it was wrong when calculating the cosine and the sine, it has the values inverted

User Rahul Bharadwaj
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