## anonymous one year ago Thanks for helping! I need to convert complex numbers into rectangular form. I'm stuck on this one: 5(cos(5pi/4)+isin(5pi/4))

1. anonymous

@Hero @perl @jim_thompson5910 @ganeshie8 @aaronq @zepdrix

2. anonymous

@TheSmartOne @Loser66 @Luigi0210

3. misty1212

HI!!

4. anonymous

hi

5. misty1212

this is not nearly as hard as it looks evaluate the functions and distribute is all

6. misty1212

do you know $$\cos(\frac{5\pi}{4})$$?

7. anonymous

-1/sqrt(2)

8. misty1212

yeah most people write $$-\frac{\sqrt 2}{2}$$ but it is the same thing

9. anonymous

I'm sort of confused about the isin though

10. misty1212

how about $$\sin(\frac{5\pi}{4})$$

11. anonymous

Is there a formula I need to follow?

12. anonymous

-sqrt(2)/2

13. misty1212

let me ask you a question how is it you know the sine, but not the cosine?

14. anonymous

?

15. misty1212

or the other way around seems like if you are able to find one, you should be able to find the other it is not like one is more difficult or something

16. misty1212

yeah they are both $$-\frac{\sqrt 2}{2}$$

17. anonymous

so I just plug it in and simplify?

18. misty1212

so $5\left (-\frac{\sqrt2}{2}-i\frac{\sqrt 2}{2}\right)$

19. anonymous

ok

20. misty1212

then distribute

21. misty1212

that is all yes

22. anonymous

oh cool

23. anonymous

thanks!

24. misty1212

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