# Converting polar and rectangular coordinates

1. Jun 14, 2009

### Entropee

So I know x=(r)cos(theta)
and y=(r)sin(theta)

As well as r^2 = x^2 + y^2
And (theta)=tan^-1 y/x or sin^-1 y/r or cos^-1 x/r

If I want to convert the polar coordinates (7.6 , 285(degrees)) to rectangular coordinates, to the nearest hundredth, what would I do?

And also if I were converting the rectangular coordinates (2.4 , 1.8) to polar.

So which variable is which in the coords? so i can plug these in and figure them out...

2. Jun 14, 2009

### arildno

Put the particular values into their appropriate places in the given equations, and solve for/compute the desired quantities.

3. Jun 14, 2009

### Entropee

Is it (r , theta)
or the other way around

4. Jun 14, 2009

### arildno

Conventionally, r is the first coordinate.

5. Jun 14, 2009

### Tibarn

If you're going from polar to rectangular for complex numbers, the x coordinate usually denotes the real part while the y coordinate denotes the imaginary part. Apart from that it's the same thing.

6. Jun 14, 2009

### Entropee

Thanks guys I think i got it :P
This is the best website ever, cant wait to start college next year :P