2008-01-16

Today's nonsense
- The quotient rule with the "lodehi" means that you have to multiply the denominator by the derivative of the entire numerator.
- Queso Fiasco
- Pezfetti.
- Phoebe's birthday- cookies, cupcakes, bigger (smelly) cupcakes,

Polar Coordinates

Given an angle and distance from the origin (radius). So it's (r, theta). And so the x value is going to be rcos(theta) and y is going to be rsin(theta). And tan(theta) = y/x, and then the Pythagorean theorem (x^2 + y^2 = r^2).

So convert (2, pi) ... so that's x=2cos(pi) and y=2sin(pi)

Know how to convert from rectangular coordinates to polar coordinates.

When converting from rectangular to polar, you take the two rectangular coordinates and do the Pythagorean theorem and get your radius.

x^2 + y^2 = a^2
r^2 = a^2
r=a you're done

y = 4
rsin(theta) = 4
or a.k.a. r = 4 csc(theta)

3x - y + 2 = 0
3rcos(theta) - rsin(theta) + 2 = 0
r = (-2) / (3cos(theta) - sin(theta)) = ...

f) y^2 = 9x
r^2 sin^2 theta = 9r cos theta
r = 9cot(theta) csc(theta)

g) r = 3
r^2 = 9
so x^2 + y^2 = 9

h) r = sin(theta)
r = y/r
r^2 = y
x^2 + y^2 = y