Understanding Polar Vector Plots and Phases in Vector Algebra

[unscientific]

Homework Statement

The problem is attached in the picture.

The Attempt at a Solution

This looks like a vector in polar notation to me (r, θ). But the application of vectors to phases and periodicity is not even mentioned in the chapter! (Vector Algebra)

I've tried to make sense of it but I'm not sure what's going on in the solutions..

What I think is this:
given 2 vectors of equal length, one with θ = 0 and another with θ = 45^o, in a given amount of time the inclined vector travels a shorter distance along x. Specifically:

x' = x cos (45)


I'm not sure if I'm correct to analyse it in this way..

 

[SammyS]

Homework Statement

The problem is attached in the picture.

The Attempt at a Solution

This looks like a vector in polar notation to me (r, θ). But the application of vectors to phases and periodicity is not even mentioned in the chapter! (Vector Algebra)

I've tried to make sense of it but I'm not sure what's going on in the solutions..

What I think is this:
given 2 vectors of equal length, one with θ = 0 and another with θ = 45^o, in a given amount of time the inclined vector travels a shorter distance along x. Specifically:

x' = x cos (45°)

I'm not sure if I'm correct to analyse it in this way..

What course is this for?

Has the textbook done anything with Phasors to analyze Alternating Current circuits?

 

[unscientific]

What course is this for?

Has the textbook done anything with Phasors to analyze Alternating Current circuits?

This is from chapter 7, Vector Algebra of "Mathematical Methods for Physics and Engineering" by Riley, Hobson and Bence.

Nope, this is the first chapter on vectors.