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))

Question

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))

anonymous · Answer

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

anonymous · Answer

@TheSmartOne @Loser66 @Luigi0210

misty1212 · Answer

HI!!

anonymous · Answer

hi

misty1212 · Answer

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

misty1212 · Answer

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

anonymous · Answer

-1/sqrt(2)

misty1212 · Answer

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

anonymous · Answer

I'm sort of confused about the isin though

misty1212 · Answer

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

anonymous · Answer

Is there a formula I need to follow?

anonymous · Answer

-sqrt(2)/2

misty1212 · Answer

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

anonymous · Answer

?

misty1212 · Answer

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

misty1212 · Answer

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

anonymous · Answer

so I just plug it in and simplify?

misty1212 · Answer

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

anonymous · Answer

ok

misty1212 · Answer

then distribute

misty1212 · Answer

that is all  yes

anonymous · Answer

oh cool

anonymous · Answer

thanks!

misty1212 · Answer

$$\color\magenta\heartsuit$$