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1. fp1 question
How do I write

6(cos(3pi/4) + iSin(3pi/4)) in the form a + ib ?

I can do it the other way, but this is harder..
2. Re: fp1 question
(Original post by sabre2th1)
How do I write

6(cos(3pi/4) + iSin(3pi/4)) in the form a + ib ?

I can do it the other way, but this is harder..
By simple expansion:

Can you get it from there?
3. Re: fp1 question
(Original post by sabre2th1)
How do I write

6(cos(3pi/4) + iSin(3pi/4)) in the form a + ib ?

I can do it the other way, but this is harder..
It shouldn't be harder; if anything it's a lot easier. What is the value of cos(3pi/4) and sin(3pi/4)? Multiply by 6 and you there you have it!
4. Re: fp1 question
(Original post by sabre2th1)
How do I write

6(cos(3pi/4) + iSin(3pi/4)) in the form a + ib ?

I can do it the other way, but this is harder..
Just work out what that comes to, it's not too hard

(6cos(3pi/4)=a)

(6sin(3pi/4)=b)
5. Re: fp1 question
(Original post by GreenLantern1)
De Moivre's Theorem
6. Re: fp1 question
(Original post by David_Skiller)
Easy don .
7. Re: fp1 question
(Original post by David_Skiller)
8. Re: fp1 question
(Original post by oli_G)
By simple expansion:

Can you get it from there?

(Original post by dknt)
It shouldn't be harder; if anything it's a lot easier. What is the value of cos(3pi/4) and sin(3pi/4)? Multiply by 6 and you there you have it!

(Original post by Fing4)
Just work out what that comes to, it's not too hard

(6cos(3pi/4)=a)

(6sin(3pi/4)=b)
ah shoulda got that ! thankss