Argument of Complex Number: Begin at (-3,2) - 135 Degrees

Click For Summary
SUMMARY

The discussion centers on the argument of the complex number expressed as arg(z + 3 - 2i) = 135 degrees, which indicates that the line from the complex number z + 3 - 2i to the origin forms a 135-degree angle with the real axis. The point (-3, 2) serves as the center for this argument, representing the complex number -3 + 2i on the Argand diagram. The vector from this point to z sweeps 135 degrees counterclockwise, leading to the conclusion that z can take any value along the line defined by the equation y = -(x + 3) + 2, or equivalently, z = x + (-x - 1)i for any real number x.

PREREQUISITES
  • Understanding of complex numbers and their representation on the Argand diagram.
  • Familiarity with the concept of the argument of a complex number.
  • Basic knowledge of coordinate geometry, specifically lines and slopes.
  • Ability to perform vector operations in the context of complex numbers.
NEXT STEPS
  • Study the properties of complex numbers, focusing on their geometric interpretations.
  • Learn how to calculate the argument of complex numbers using different methods.
  • Explore the relationship between complex numbers and polar coordinates.
  • Investigate the implications of complex number transformations on the Argand plane.
USEFUL FOR

Students beginning their journey in complex numbers, educators teaching complex analysis, and anyone interested in the geometric interpretation of complex arithmetic.

Solidmozza
Messages
29
Reaction score
1
Hi everybody!
Could somebody please assist me with an explanation as to why the following: arg (z+3-2i) = 135degrees : has its centre at -3,2 and that is the place where you begin the argument (ie go 135 degrees)
Please note, just beginning complex numbers. Sorry if can't understand question.
Thanks.
 
Physics news on Phys.org
It would be nice to tell us exactly what you are trying to find! I.e. what do you go 135 degrees to?

The statement that "arg(z+ 3- 2i)= 135 degrees" means that the line from the number z+3- 2i to the origin (0) makes a 135 degree angle with the real axis. I imagine the problem asks you to determine possible values for z.
Write z+ 3- 2i as z- (-3+ 2i). The complex number -3+ 2i is represented on the Argand diagram by the point (-3, 2). We can think of z- (-3+2i) as a vector with its tail at (-3, 2) and its point at z. Now, starting from a horizontal line (parallel to the real axis), sweep 135 degrees counter clockwise (that gets you to the "upper left" quadrant, 45 degrees from either axis). z could be any point on that line. If this line were through (0,0) on an xy- plane, it would be the line y= -x: slope -1. Since it must go through (-3, 2), it has equation y= -(x+3)+ 2= -x- 1: z = x+(-x-1)i for x any real number.
 

Similar threads

Replies
4
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
39
Views
6K
  • · Replies 1 ·
Replies
1
Views
8K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 3 ·
Replies
3
Views
2K