Finding Trajectory of x & y in Kinematics

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The discussion focuses on finding the trajectory of a point defined by the equations x = 4cos(2t) + 3sin(2t) and y = 3cos(2t) - 4sin(2t). Participants note that since sine and cosine functions repeat every 2π, the trajectory will also repeat, and they seek to determine the period of this repetition. To find the trajectory, the equations can be squared and summed, leveraging the identity cos² + sin² = 1. Additionally, the task involves calculating the velocity and acceleration of the point at t = π seconds. The conversation emphasizes understanding the mathematical process behind deriving the trajectory.
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Thread moved from a technical forum, yada, yada... :-)
I need to find a trajectory

x = 4cos(2t) + 3sin(2t)
y = 3cos(2t) - 4sin(2t)
 
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Kitanov said:
I need to find a trajectory
Will it repeat?
How often?
 
Baluncore said:
Will it repeat?
How often?

I don't know what you think will happen again.
That's the whole task, there is no explanation of how the task is done. I can send you where that task is from, but you won't understand anything because it's in Serbian.

http://www.tfzr.uns.ac.rs/Content/files/0/Kinematika - I deo.pdf
Task 2
 
The trajectory is a function of 2t.
Sine and cosine repeat evert 2π, so the trajectory will repeat. What period?
Plot values of x and y against t.
 
Serbian is easy with google translate...
Page 6 of the .pdf
The question and a solution is presented on that page. I translate, but not all the equations.

Zadatak 2: Kretanje tačke određeno je jednačinama =
Task 2: The motion of a point is determined by equations

𝑥=4cos(2𝑡)+3sin(2𝑡)
𝑦=3cos(2𝑡)−4sin(2𝑡)
(𝑥, 𝑦 - in meters, 𝑡 - in seconds)

Odrediti trajektoriju (putanju), brzinu i ubrzanje tačke u trenutku kada je 𝑡=𝜋[𝑠]
= Determine the trajectory (trajectory), velocity and acceleration of a point at the moment when 𝑡 = 𝜋[𝑠]

Rešenje: = Solution:
Trajektorija (putanja) = Trajectory (path)
Dobijene jednačine kvadrirati i sabrati = Square and add the obtained equations
Brzina = Speed.
Ubrzanje = Acceleration.
 
Baluncore said:
Serbian is easy with google translate...
Page 6 of the .pdf
The question and a solution is presented on that page. I translate, but not all the equations.

Zadatak 2: Kretanje tačke određeno je jednačinama =
Task 2: The motion of a point is determined by equations

𝑥=4cos(2𝑡)+3sin(2𝑡)
𝑦=3cos(2𝑡)−4sin(2𝑡)
(𝑥, 𝑦 - in meters, 𝑡 - in seconds)

Odrediti trajektoriju (putanju), brzinu i ubrzanje tačke u trenutku kada je 𝑡=𝜋[𝑠]
= Determine the trajectory (trajectory), velocity and acceleration of a point at the moment when 𝑡 = 𝜋[𝑠]

Rešenje: = Solution:
Trajektorija (putanja) = Trajectory (path)
Dobijene jednačine kvadrirati i sabrati = Square and add the obtained equations
Brzina = Speed.
Ubrzanje = Acceleration.

I speak Serbian. I understand what is written there, but it was not clear to me why it is done that way.
Now it is.
 
Kitanov said:
I need to find a trajectory

x = 4cos(2t) + 3sin(2t)
y = 3cos(2t) - 4sin(2t)
express ##\cos 2t## and ##\sin 2t## and use ##\cos^2+\sin^2=1##
 
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