Motion of Point P in Complex Plane: Finding z(t)

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Homework Help Overview

The discussion revolves around the motion of a point P in the complex plane, specifically defined by the equation z^5 = (1 + t)^i. Participants are tasked with finding z(t) and demonstrating that P undergoes circular motion, including determining velocity and acceleration as functions of time.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the interpretation of the term 'principal root' and its implications for solving the equation. There are questions about whether to take the root of both sides and how to isolate z. Some express uncertainty about the terminology and its application to the problem.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some have offered insights into the nature of complex roots, while others are seeking clarification on the terminology used in the question.

Contextual Notes

There is mention of a lack of familiarity with the term 'principal root' among some participants, which may affect their understanding of the problem. Additionally, the nature of the roots in relation to the equation z^4 - 1 = 0 is brought up, indicating a potential area of confusion.

fizzo68
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The motion of a point P in the complex plane is defined by the
principal root of z^5= (1+ t)^i

a)find z(t)
b)Show that P is undergoing a circular motion. Find the velocity
and acceleration as a function of time

I'm pretty sure I know how to do b but I don't really understand the wording of the question. A is really confusing me. The 'Principal root' would that mean I have to take the root of both sides? and then just rearrange and isolate z?
 
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The function z(t) describes the motion of the point in the x,y plane. So you need to take the fifth root of both sides of the equation to get z(t). As you know, there are 5 fifth roots of a complex number, you have to take the principal one. ehild
 
fizzo68 said:
The motion of a point P in the complex plane is defined by the
principal root of z^5= (1+ t)^i

a)find z(t)
b)Show that P is undergoing a circular motion. Find the velocity
and acceleration as a function of time

I'm pretty sure I know how to do b but I don't really understand the wording of the question. A is really confusing me. The 'Principal root' would that mean I have to take the root of both sides? and then just rearrange and isolate z?

Ask Dr. Euler for help.

(I have to confess, I never heard the term 'principal root' before. I believe, with deep conviction , that all roots are created equal.) :smile:
 
rude man said:
Ask Dr. Euler for help.

(I have to confess, I never heard the term 'principal root' before. I believe, with deep conviction , that all roots are created equal.) :smile:

well, there is a qualitative difference between the 2 roots of z4 - 1 = 0, 1 and i, in the sense that 1 is a power of i, but not vice versa.
 
Deveno said:
well, there is a qualitative difference between the 2 roots of z4 - 1 = 0, 1 and i, in the sense that 1 is a power of i, but not vice versa.

EIDT EDIT: Oops, I still get a straight line, magnitude [ln(1+t)]^0.2 and angle 0.2 rad.

Someone else please join in?
 
Last edited:

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