SOLUTION: Convert the polar equation to rectangular coordinates. (Use variables x and y as needed.) r = −3

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Question 1131216: Convert the polar equation to rectangular coordinates. (Use variables x and y as needed.)
r = −3

Found 4 solutions by MathLover1, ikleyn, MathTherapy, greenestamps:
Answer by MathLover1(20850)   (Show Source): You can put this solution on YOUR website!

given:
the relationships between rectangular and polar coordinates are:


..........square both sides

->which is a circle centered in the origin and with radius of


Answer by ikleyn(52830)   (Show Source): You can put this solution on YOUR website!
.
Convert the polar equation to rectangular coordinates. (Use variables x and y as needed.)
r = −3
~~~~~~~~~~~~~~~~~~~

Traditionally, in polar coordinates, the variable " r " is the distance from the origin in a coordinate plane.


In polar coordinates, the radius r should be non-negative to describe non-empty set of points.


In your case, with r negative  r= -3, it describes EMPTY set of points.

The answer by @MathLover1 is incorrect.


Answer by MathTherapy(10555)   (Show Source): You can put this solution on YOUR website!
Convert the polar equation to rectangular coordinates. (Use variables x and y as needed.)
r = −3
"r" CANNOT be negative, so IGNORE the person who claims that it can be.
It can be 0, but not < 0. In other words,
Answer by greenestamps(13203)   (Show Source): You can put this solution on YOUR website!


I will disagree with tutors @MathTherapy and @ikleyn, both of whom say the solution is the empty set and the solution by tutor @MathLover1 is incorrect.

In polar coordinates, r can be negative. (-3,pi/2) is a valid description of a point in polar coordinates; so it is a point on the graph of r=-3.

Any point with polar coordinates (3,theta) can be represented also by (-3,theta+pi); or with an infinite number of other representations with r equal to either 3 or -3. So the graph of r=-3 is the same as the graph of r=3.

If it were the case that r can't be negative, then simple polar equations like r=sin(theta) or r = -2+cos(theta) would be invalid.

The equation r=-3 is independent of the angle theta; it is equivalent to the equation r=3. Both equations are of a circle with center at the origin and radius 3.

As tutor @MathLover1 said, the equation in rectangular coordinates is


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