How do you convert the polar equation r=8cscthetar=8cscθ into rectangular form?

2 Answers
Sep 28, 2016

y=8y=8

Explanation:

The relation between polar coordinates (r,theta)(r,θ) and rectangular Cartesian coordinates (x,y)(x,y) is given by

x=rcosthetax=rcosθ and y=rsinthetay=rsinθ

Hence r=8csctheta=8/sinthetar=8cscθ=8sinθ

or rsintheta=8rsinθ=8

or y=8y=8

Sep 28, 2016

y = 8y=8

Explanation:

The conversion equation is r(cos theta, sin theta)=(x, y)r(cosθ,sinθ)=(x,y), giving

r = sqrt(x^2+y^2)r=x2+y2 (principal square root) >=00,

cos theta = x/sqrt(x^2+y^2) and sin theta =y/sqrt(x^2+y^2)cosθ=xx2+y2andsinθ=yx2+y2.

Here, r>=rminimum (8csc theta)=8(8cscθ)=8, for theta in (0, pi)θ(0,π) .

Now, r=8csc theta =8/sin theta=8r/yr=8cscθ=8sinθ=8ry.

Cancelling non-zero r,

y=8y=8

Interestingly,

as theta to 0_+, csc theta to ooθ0+,cscθ and,

as theta toθ 0_, csc to -oo_,csc.

Likewise, there is irremovable infinite discontinuity at theta=piθ=π.

So, it is proper to state that

y = 8, x in (-oo, oo)y=8,x(,), in cartesian form, is equivalent to

r=8 csc theta, theta in (0. pi)r=8cscθ,θ(0.π), in polar form.

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