HELP Absolute Values on a Complex Plane

[wadahel]

Homework Statement

Draw |z| on a complex plane, where z = -3+4i

Homework Equations

N/A

The Attempt at a Solution

[PLAIN]http://img530.imageshack.us/img530/1786/aaakr.jpg
Can anyone please tell me which answer is correct?
Both of them have a moduli of 5.
So should the circle centred at the origin or at (-3,4i)?

 

[issacnewton]

are you trying to draw |z|=5 ? in that case, your first graph is correct since origin should lie
on the circle because the distance between the origin and (-3,4i) is 5..

 

[Mark44]

are you trying to draw |z|=5 ? in that case, your first graph is correct since origin should lie
on the circle because the distance between the origin and (-3,4i) is 5..

The OP doesn't say anything about graphing |z| = 5, just |z|.

If z = -3 + 4i, then |z| = 5. This would be a single point on the Re axis 5 units to the right of the origin.

 

[HallsofIvy]

I suspect that wadahel has misunderstood the question. Graphing the number "5" on the complex plane doesn't make a lot of sense. wadahel, what was the exact wording of the problem? Are you go graph "|z| where z= -3+ 4i" or "graph all z such that |z|= |-3+ 4i|"

 

[wadahel]

The question says if z = -3+4i, determine |z| and use complex plane diagrams to illustrate their relationship with the original complex number.
thanks!

 

[Mark44]

That still doesn't make a lot of sense. In this case |z| = 5. "... illustrate their relationship ..." "Their" implies two or more things, but here you have only one thing: |z|.

About the only relationship I can think of is that -3 + 4i determines one vertex in a right triangle, and 5 is the length of the hypotenuse of that triangle.