complex No. (1 Viewer)

[chousta]

yep

 

[bos1234]

ok dear sir

im due for my afternoon nap now.. goodnight

 

[chousta]

hahahaha???/

 

[dr baby beanie]

z1 = r1 (cos@ + isineB) which then becomes z1 = r1 cis@
z2 = r2 (cosB + isineB) which then becomes z2 = r2 cisB

now by DT's theorum: z1/z2 = r1/r2 cis(@-B)

which then when you expand out the cis(@-B) part becomes
z1/z2 = r1/r2 [cos(@-B) + isine(@-B)]

which is want you want isn't it?

However the other ppl who answered your questions early probably know more about it, and their's is probably more right than mine

Hope I'ved helped anway

 

[chousta]

k, its just that the questions is a proof of the therm. so i dont think you can use the therm itself to prove it, coz thats wat i had originally(and that makes it easy) but the question is to prove the therm.

 

[dr baby beanie]

lolz, k I gettcha, that's also what I was sort of asking too ^^ about the 'proof'

 

[dr baby beanie]

What text book is this question from?

 

[chousta]

dr Baby I GOT IT!@!!!

and it was really really easy!! i feel (ashamed)

 

[kony]

1/Z2 = 1/r2 * cis (-B)

therefore, Z1.1/Z2 = r1/r2 * (cosA+isinA)(cosB-isinB)

=r1/r2 * (cosAcosB - sinBcosAi + cosAsinBi + sinAsinB)
=r1/r2 * [cos(A-B) - (sinBcosAi - cosAsinBi)]
=r1/r2 * [cos(A-B) - isin(A-B)]

 

[adgala]

kony's answer was 4 minutes later than your answer, he was probably writing it when you posted.

 

[pLuvia]

chousta in the future please don't delete your threads, because people may want to look at the solutions or people might ask the same questions thank you

 

[haque]

dr Baby I GOT IT!@!!!

and it was really really easy!! i feel (ashamed)

Yep that's what i said(maybe i should have mentioned properties of sine as well )

 

[dr baby beanie]

Well done chousta!!

hmmm it uses trig, might have revise it

 

[Slidey]

On top of what pLuvia said, it might be a good idea in future to post new questions of the same focus in a single thread. For example, all these complex number questions could have been contained within one thread. That way you needn't delete a thread because it seems trivial.

(The posts may seem out of order - your three complex number threads, all bearing the same name, have been merged.)