## anonymous 3 years ago Write the expression in the standard form a + bi. (View my question to see it written, sorry for the inconvenience)

1. anonymous

|dw:1352848428519:dw|

2. anonymous

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

3. asnaseer

4. anonymous

Is it wrong? i used De Moivre's Theorem

5. asnaseer

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

6. anonymous

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

7. anonymous

Not sure what you mean by that

8. asnaseer

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. anonymous

|dw:1352848854469:dw|

10. anonymous

i used this form

11. asnaseer

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. anonymous

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

13. asnaseer

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

14. asnaseer
15. anonymous

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

16. asnaseer

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

17. asnaseer

yup - you got it!