Understanding Vectors: Magnitude and Angle Calculation

  • Context: High School 
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Discussion Overview

The discussion revolves around understanding vectors, specifically focusing on the calculation of magnitude and angle for the vector represented as 2 + j2. Participants explore the interpretation of the vector in a two-dimensional plane and clarify the concepts of magnitude and angle in relation to this vector.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the understanding of the vector's magnitude, initially suggesting it is negative, which prompts confusion.
  • Another participant explains that the vector represents a point in a two-dimensional plane, detailing how to calculate the magnitude and angle, asserting that the angle is 45 degrees due to the equal components of the vector.
  • A later reply emphasizes the importance of correctly identifying the imaginary unit, noting that "j" is used in electrical engineering while "i" is standard in mathematics, which leads to a different interpretation of the vector's properties.
  • There is a clarification about the angle calculation, with one participant providing a method involving the arctangent function.
  • One participant expresses gratitude for the help received and acknowledges their initial confusion.

Areas of Agreement / Disagreement

Participants exhibit some disagreement regarding the interpretation of the imaginary unit and the initial claim about the magnitude. While some agree on the method to find the angle and magnitude, others challenge the initial assumptions, leading to an unresolved discussion on the correct terminology and interpretation.

Contextual Notes

There are unresolved issues regarding the use of "j" versus "i" for the imaginary unit, and the initial misunderstanding about the magnitude being negative. The discussion reflects varying levels of familiarity with vector representation and terminology.

Dx
[SOLVED] Vectors help?

The vector 2 + j2 is the same as what?

I know that j2 is -1 so the answer would be -2 for the magnitude but what about the angle in degrees? I don't comprehend the problem can anyone help make sense outta this for me, please!
Dx :wink:
 
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A negative magnitude?

I'm sorry but I didnt understand your question very well.
 
DX,
I don’t follow what you’re doing at all. That problem represents a point in a two-dimensional plane, and it is found in reference to both a horizontal and vertical axis. The first number is how far you move along the horizontal axis and the second is how far you move along the vertical. Because both numbers are positive, not negative, you will be going to the right 2 units and upward 2 units, placing the point in quadrant number one. Because the real part (2) and the imaginary part (j2) are of equal magnitude this is going to form a square, and the angle you will always get with a square is 45 degrees. But, the math goes like this;

C = 2 + j2
C = [squ][(2)2 + (2)2] = the magnitude you need to find.

And;

[the] = tan-1(2/2) = the angle you need to find.

In the equation to find the angle, where the 2/2 is located, the number that goes in the numerator will be the imaginary j value and the denominator will be the real value. This would have been easier to see if the values hadn’t been the same.

Hope that helps,
Good luck.

[edit]
I should expand a little about the square always having 45 degrees; If the point resides in quadrant one it is 45, in quad-2 it is 90 + 45, and so on.
 
Last edited by a moderator:
Sorry to have confused everybody. I was trying to make sense outa this problem but didn't realize I confused you guys along with myslef. :wink:
I got it Boulderhead, THANKS!
Dx :wink:
 
You're welcome!
Do you have a good calculator?
 
Originally posted by BoulderHead
You're welcome!
Do you have a good calculator?

Its not the latest and greatest but me and my TI-83 have been though good times n bad. :wink:
Dx
 
One thing that is confusing to me is your statement "I know that j2 is -1". This is a mathematics forum and mathematicians use i for the imaginary unit. Only electricians use "jmaginary" numbers!

Assuming that that is what you mean (and that you mean "^2" or squared rather than "j2") then 2- i^2= 2-(-1)= 3.

The "degrees" would be 0 since this is a real number.
 

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