Finding the Coordinates of a Point Using Rectangular and Polar Formulas

[ArcadianGenesis]

Homework Statement

The rectangular and polar coordinates of a point are (x,y) and (r,theta) where x = 7 and theta = 52 degrees. Determine r and y.

Homework Equations

r = srt(x^2 + y^2)
theta = arctan(y/x)
x = rcos(theta)
y = rsin(theta)

The Attempt at a Solution

I tried to assume that r and x would be the same, so I let r = 7, which would then make y = 5.5. But that's wrong. What else can possibly be done?

 

[ooellis]

2 equations, 2 unknowns

Use:
x=rcos(theta) eqn. 1
y=rsin(theta) eqn. 2

Since you know what x and theta are you can solve for r in eqn. 1.

Then once you know r you can plug that into eqn. 2 and solve for y.

 

[ArcadianGenesis]

Haha, nice. I was having one of those mental blocks that just would not allow me to think of that. Thanks.