Parametric equation to cartesian

In summary, the problem is to find the cartesian equation for x = sec(t) and y = tan(t). The solution involves using the identity 1 + tan^2(t) = sec^2(t).
  • #1
Mrencko
109
0

Homework Statement


I have this equation and i need to find the cartesian equation, so i apreciate your help

Homework Equations


X=cost ' y=2sin2t

The Attempt at a Solution


I am usign this [/B]
Sin2t=2costsint
So x+y/2=cost+2costsint
But i don't know what to do after,
I also try to solve that this way
Y/2=sin2t
Y/2=2costsint then sint=y/(4cost)
Y/2=2((x)y/4x)
When i isolate y i get y/y=3x-2
 
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  • #2
Mrencko said:

Homework Statement


I have this equation and i need to find the cartesian equation, so i apreciate your help

Homework Equations


X=cost ' y=2sin2t

The Attempt at a Solution


I am usign this [/B]
Sin2t=2costsint
So x+y/2=cost+2costsint
But i don't know what to do after,
I also try to solve that this way
Y/2=sin2t
Y/2=2costsint then sint=y/(4cost)
Y/2=2((x)y/4x)
When i isolate y i get y/y=3x-2
So y = 4sin(t)cos(t). What is y/x?

Ideally, you want to get something that involves sin2(t) + cos2(t), which equals 1, and eliminates the parameter t.
 
  • #3
Thanks for the help i juts figure out how to get rid of that parameter 1-cos alll div by 2
 
  • #4
Mrencko said:
Thanks for the help i juts figure out how to get rid of that parameter 1-cos alll div by 2
I doubt that will work.
 
  • #5
y=4xsint==>y^2=16x^2(1(cost)^2)=y^2=16x^2(1-x^2)
 
  • #6
Forget about div for 2
 
  • #7
Mrencko said:
y=4xsint==>y^2=16x^2(1(cost)^2)=y^2=16x^2(1-x^2)
With one correction, that works. Where you have y2 = 16x2(1(cost)^2), it should be y2 = 16x2(1 - cos2(t)). Otherwise, what you ended with is the same as I got.
 
  • #8
Thanks that's it Sorry pal i have anoter problem i am doing x=sect y=tant
So what i need to do use the 1+tan^2=sec^2
Or use the sin/cos=tan and 1/cos = sec? I can get the solution
 
  • #9
Mrencko said:
Thanks that's it Sorry pal i have anoter problem i am doing x=sect y=tant
So what i need to do use the 1+tan^2=sec^2
Or use the sin/cos=tan and 1/cos = sec? I can get the solution
Using ##1 + \tan^2\theta = \sec^2\theta## is the obvious choice. But you should post new questions in new threads if you don't want to have your hand slapped by a moderator.
 
  • #10
Mrencko said:
Thanks that's it Sorry pal i have anoter problem i am doing x=sect y=tant
So what i need to do use the 1+tan^2=sec^2
Or use the sin/cos=tan and 1/cos = sec? I can get the solution
This is a new problem, so please start a new thread.
 

1. What is a parametric equation?

A parametric equation is a set of equations that express a set of variables, typically denoted as x and y, as functions of an independent variable, typically denoted as t. It is commonly used to represent curves and surfaces in mathematics and physics.

2. How is a parametric equation converted to cartesian form?

To convert a parametric equation to cartesian form, the independent variable t is eliminated by solving for it in one of the equations and substituting the result into the other equation. This will result in an equation in terms of x and y, which is the cartesian form.

3. What are the advantages of using parametric equations?

Parametric equations allow for a more efficient and versatile way of representing curves and surfaces, especially ones that are not easily expressed in cartesian form. They also provide a way to represent motion and changes over time, making them useful in physics and engineering.

4. Can any curve be represented by a parametric equation?

Yes, any curve can be represented by a parametric equation. However, some curves may be more easily expressed in cartesian form, while others may require more complex parametric equations to accurately represent them.

5. How are parametric equations used in real-world applications?

Parametric equations are used in a variety of real-world applications, including computer graphics, engineering, and physics. They are particularly useful for representing motion, such as the trajectory of a projectile, and for creating 3D models of objects and surfaces.

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