Complex no.s raised to exponents & divided...

Hi guys,

i have a problem...it goes like this:

Given: z1= 2,5+8i and z2= 0,5-3i

2) Now Calculate: (z1)^2/(z2)^3

This is what my answer looks like: -947,969/874,704 - 1309,438i/874,704

I need to know where i went wrong please?

Thanks in advance...

Re: Complex no.s raised to exponents & divided...

Quote:

Originally Posted by

**Toyboy** Given: z1= 2,5+8i and z2= 0,5-3i

Now Calculate: (z1)^2/(z2)^3

This is what my answer looks like: -947,969/874,704 - 1309,438i/874,704

I need to know where i went wrong please?

Well, (5/2 + 8i)^2 = (160i - 231) / 4

and (1/2 - 3i)^3 = (198i - 107) / 8

SO:

[(160i - 231) / 4] / [(198i - 107) / 8] = (320i - 462) / (198i - 107)

Hope that helps...

Re: Complex no.s raised to exponents & divided...

But since you don't tell us what you **did** there is no way to say what, if anything, you did wrong!

Re: Complex no.s raised to exponents & divided...

Quote:

Originally Posted by

**HallsofIvy** But since you don't tell us what you **did** there is no way to say what, if anything, you did wrong!

My apologies, this is what i did:

(2,5+8i)^2/(0,5-3i)^3

(2,5+8i)(2,5+8i)/(0,5-3i)(0,5-3i)(0,5-3i)

....mulitplied it all out and ended up with this: -947,969/874,704 - 1309,438i/874,704

Re: Complex no.s raised to exponents & divided...

Quote:

Originally Posted by

**Toyboy** (2,5+8i)(2,5+8i)

Do you get what I got when you complete that one...see my previous post... ??

Re: Complex no.s raised to exponents & divided...

Quote:

Originally Posted by

**Wilmer** Do you get what I got when you complete that one...see my previous post... ??

Sorry i missed your post...

Nope, it does not, mine equates to -1.084-1.497i

Your answer equates to 4.318+1.61(recurrring 61)

Re: Complex no.s raised to exponents & divided...

Sorry, but got no idea what you're talking about or doing...

mine equates to -57.75 + 40i ; or to -17.75 if 1 is used instead of i

I'll ask you once more:

I get: (2.5 + 8i)^2 = (160i - 231) / 4

What do you get: (2.5 + 8i)^2 = ?

Re: Complex no.s raised to exponents & divided...

Quote:

Originally Posted by

**Toyboy** Given: z1= 2,5+8i and z2= 0,5-3i

2) Now Calculate: (z1)^2/(z2)^3

This is what my answer looks like: -947,969/874,704 - 1309,438i/874,704

$\displaystyle \frac{{z1}^2}{{z2}^3}=2.22 +1.13 i$

Re: Complex no.s raised to exponents & divided...

Quote:

Originally Posted by

**MaxJasper** $\displaystyle \frac{{z1}^2}{{z2}^3}=2.22 +1.13 i$

Agree. (320i - 462) / (198i - 107) = ~2.226798 + ~1.129962 i