How do i convert a polar equation into a cartesian equation

[Aganack1]

So anyone know how i can convert this equation(r=cos(3Ø)) into a cartesian eqation?

 

[Chunkee]

add lager beer

 

[Heisenberg]

Here's a hint: cos(3t) = 4*cos(t)^3 ?3*cos(t).

 

[bigalt]

it's easier to figure out how to do it the other way, and then invert it.

if you were given an x and a y value, how would you express the distance of that in terms of r and theta?

 

[Legendary]

x=rcos(theta)

 

[simms]

I hate polar coordinates. That was the worst part of Calculus II.

 

[Trevelyan]

All you need to know:

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

 

[DrPizza]

Originally posted by: simms
I hate polar coordinates. That was the worst part of Calculus II.

I always forget that they're part of calc II, I teach polar coordinates in pre-calc so I can do more in calculus.

 

[NuclearNed]

Originally posted by: simms
I hate polar coordinates. That was the worst part of Calculus II.

I love polar coordinates. I taught an hour-long university seminar on the topic.

 

[hdeck]

i learned polar coordinates in pre-cal...so long ago

trevelyan answered the question the best.