Re: vectors

From: Lynn Kurtz (kurtzDELETE-THIS_at_asu.edu)
Date: 01/29/05 

Date: Sat, 29 Jan 2005 19:51:47 GMT

On Sat, 29 Jan 2005 17:10:10 -0000, xxx@yyy.zzz (Northstar) wrote:

>In article <jev6QSav+dlMy1OHEGy+avWFbziQ@4ax.com>, kurtzDELETE-THIS@asu.edu
>says...
>>
>>On Fri, 28 Jan 2005 22:00:47 -0000, xxx@yyy.zzz (Northstar) wrote:
>>
>>>
>>>Hi all. Need help please. If R=9.953 and Z=32.99, what is X ?
>>>
>>>Is this the case? Since Z=R+jX , does X=Z-jR ,
>>
>>no
>>
>>>i.e X=sqrt(Z^2-R^2) ?
>>
>>and that wouldn't be true even if it was yes above.
>>
>>You are apparently learning about complex numbers and are confusing
>>the magnitude of a complex number with the number itself. For example
>>if Z = R + j X then R and X are the real and imaginary parts of Z, and
>>the magnitude of Z is given by |Z| = sqrt(R^2 + Z^2). So I am guessing
>>that you don't mean Z = 32.99 (a real number) while also Z = R + jX, a
>>complex number. You need to state your problem more carefully and
>>correctly to get better help with it.
>>
>>--Lynn
>
>
>Sorry. The question is: R = 9.953, magnitude of Z = 32.99, what is X,
>and how to state the equation for X? TIA
>
>

So I gather you are saying that Z = R + j X where R = 9.953 so
Z = 9.953 + j X. Then if |Z| = 32.99 that says:

32.99 = sqrt(9.953^2 + X^2)

You can solve that for X if you begin by squaring both sides.

--Lynn