Convert the polar equation to rectangular form.

In summary, the conversation discusses how to simplify the equation r=3sinθ and use it to find an xy equation. It suggests using the equations x=rcosθ and y=rsinθ to express both sin(θ) and r in terms of x and y. It also mentions using the equation r^2=x^2+y^2 to solve for y in terms of x.
  • #1
Lebombo
144
0

Homework Statement



r = 3sin[itex]\theta[/itex]

since

x= rcos[itex]\theta[/itex]

x = 3sin[itex]\theta[/itex]cos[itex]\theta[/itex]

and since:

y = rsin[itex]\theta[/itex]

y = 3[itex]sin^2\theta[/itex]


Then I'm sort of stuck..
 
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  • #2
Lebombo said:

Homework Statement



r = 3sin[itex]\theta[/itex]

since

x= rcos[itex]\theta[/itex]

x = 3sin[itex]\theta[/itex]cos[itex]\theta[/itex]

and since:

y = rsin[itex]\theta[/itex]

y = 3[itex]sin^2\theta[/itex]


Then I'm sort of stuck..

You are making it way too difficult. Put ##\sin\theta =\frac y r## in your first equation then see if you can get an xy equation from that.
 
  • #3
Lebombo said:

Homework Statement



r = 3sin[itex]\theta[/itex]

since

x= rcos[itex]\theta[/itex]

x = 3sin[itex]\theta[/itex]cos[itex]\theta[/itex]

and since:

y = rsin[itex]\theta[/itex]

y = 3[itex]sin^2\theta[/itex]


Then I'm sort of stuck..

Try putting sinθ=y/r.
 
  • #4
LCKurtz said:
You are making it way too difficult. Put ##\sin\theta =\frac y r## in your first equation then see if you can get an xy equation from that.


Like so:

r = 3sinθ becomes (r=3[itex]\frac{y}{r}[/itex])

= (r =[itex]\sqrt{3y}[/itex]) ?


or solving for y, (y = [itex]\frac{r^2}{3}[/itex])



or do you mean something like this:



([itex]\frac{y}{r} = sinθ [/itex]) becomes ([itex]\frac{y}{3sinθ} = sinθ[/itex])


= (y = 3sin[itex]^{2}θ[/itex])
 
  • #5
Lebombo said:
Like so:

r = 3sinθ becomes (r=3[itex]\frac{y}{r}[/itex])

= (r =[itex]\sqrt{3y}[/itex]) ?or solving for y, (y = [itex]\frac{r^2}{3}[/itex])
or do you mean something like this:
([itex]\frac{y}{r} = sinθ [/itex]) becomes ([itex]\frac{y}{3sinθ} = sinθ[/itex])= (y = 3sin[itex]^{2}θ[/itex])

You also want to use ##r^2=x^2+y^2##. You need to express both ##sin(\theta)## and r in terms of x and y. Try once more.
 

Related to Convert the polar equation to rectangular form.

What is a polar equation?

A polar equation is a mathematical representation of a curve on a polar coordinate system, where points are defined by a distance from the origin and an angle from the positive x-axis.

Why would I need to convert a polar equation to rectangular form?

Converting a polar equation to rectangular form can make it easier to graph and analyze, especially if the equation involves complex or nested trigonometric functions.

How do you convert a polar equation to rectangular form?

To convert a polar equation to rectangular form, use the following formulas: x = rcosθ and y = rsinθ, where r is the distance from the origin and θ is the angle from the positive x-axis.

Are there any limitations to converting a polar equation to rectangular form?

Yes, converting a polar equation to rectangular form only works for equations that can be expressed as a function of θ. Equations with multiple values of θ (e.g. spirals or rose curves) cannot be converted using this method.

Can you convert a rectangular equation to polar form?

Yes, you can convert a rectangular equation to polar form using the following formulas: r = √(x^2 + y^2) and θ = tan^-1(y/x). However, some rectangular equations may not have an equivalent polar form.

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