## student1988 Group Title Write the expression in the standard form a + bi. (View my question to see it written, sorry for the inconvenience) one year ago one year ago

1. student1988 Group Title

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2. student1988 Group Title

That's raised to the fourth power.. I got -4. Can someone tell me if i am correct? :)

3. asnaseer Group Title

4. student1988 Group Title

Is it wrong? i used De Moivre's Theorem

5. asnaseer Group Title

so did you first convert it to the form $$e^{i\theta}$$?

6. student1988 Group Title

but i wasn't sure if it was right because the complex number i disappeared!

7. student1988 Group Title

Not sure what you mean by that

8. asnaseer Group Title

your answer is correct - I am just making sure you used this way of getting to the answer rather than trying to expand the braces with the fourth power :)

9. student1988 Group Title

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10. student1988 Group Title

i used this form

11. asnaseer Group Title

the method I used was to first convert it as follows:$(\sqrt{2}(\cos(3\pi/4)+i\sin(3\pi/4))^4=(\sqrt{2}e^{i3\pi/4})^4$

12. student1988 Group Title

oh, i haven't seen this form. Could you tell me where I can read on this form?

13. asnaseer Group Title

it uses the identity:$e^{i\theta}=\cos(\theta)+i\sin(\theta)$

14. asnaseer Group Title
15. student1988 Group Title

Euler's Formula. Thanks, i'll read it! Thank you! :)

16. asnaseer Group Title

Sorry - wrong link, I meant this one: http://en.wikipedia.org/wiki/Euler%27s_formula

17. asnaseer Group Title

yup - you got it!