July 17th, 2015, 01:56 AM  #1 
Member Joined: Aug 2013 Posts: 31 Thanks: 1  Locus
Hi guys, any help with this one would be great. Z is a complex number. Sketch the locus of z that satisfied by: arg(z2/zi)=pi/4. I break this down to: arg(z2)arg(zi)=pi/4 My thought is to select three points and place them on the imaginary axis, then deduce the coordinate of z, three times, (ie start with z on the im axis, and we can show that coordinate of z is (0,2),then place z2 on the im axis etc) Has anyone got an easier way to do this? I know the answer is a circle, but how can you tell? also, My the answer shows its just a major arc of a circle, but with no explanation as to why only part of the circle exists. if anyone can help deduce the equation and help with the above I would be appreciate it. Thanks in advance 
July 17th, 2015, 01:41 PM  #2 
Global Moderator Joined: May 2007 Posts: 6,205 Thanks: 487 
$\displaystyle \frac{z2}{zi}=r\frac{\sqrt{2}}{{2}}(1+i)$, where r > 0. Solve for r as a function of z and plot.


Tags 
locus 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Locus  Monokuro  Geometry  5  August 2nd, 2014 07:37 PM 
Known locus?  Mathmax  Algebra  0  May 22nd, 2011 12:09 PM 
Locus  julian21  Algebra  1  November 8th, 2010 08:26 PM 
LOCUS  symmetry  Algebra  6  January 30th, 2007 03:48 AM 