math

posted by .

convert to polar form:

1) x^2-y^2=4 (You may leave your answer for this one as r2 =)

2) x^2+(y-1)^2=1

• math -

we know
r^2 = x^2 + y^2
x/r = cosØ, and y/r = sinØ or x=rcosØ and y = rsinØ

x^2 - y^2 = 4
r^2 cos^2 Ø - r^2 sin^2Ø = 4
r^2 (cos^2 Ø - sin^2 Ø) = 4
r^2 (cos 2Ø)=4
r^2 = 4/cos 2Ø or r^2 = 4sec 2Ø

follow the same procedure for the second one, let me know what you got

• math -

how did you get cos 2Ø after subtracting cos^2Ø-sin^2Ø?

• math -

One of the basic trig identities says:

cos 2A = cos^2 A - sin^2 A

Similar Questions

1. precalculus

5x+3y=8 convert each rectangular equation to polar form Convert each polar equation to rectangular form: a r=9cos0 b r=5 c rsq= cos 20 d r= 3____ 3+sin 0 Is this a test?
2. Maths - Polar Coordinate Systems

I've received an assignment to investigate the polar coordinate system compared to the cartesian one. Theres a question that asks you to investigate into how to convert polar coordinates into cartesian. From my text book, I know in …
3. pre-calculus

convert the numbers to polar form and then divide.leave the answer in polar form. 10-10i/3root3+3i
4. precalculus

convert the equation y^2 = 2x -x^2 into polar form. convert the equation r = 2tan(theta) into rectangular form. I'm not really sure what either of these mean. I vaguely understand polar coordinates, but I'm not sure how to convert …
5. PRECALCULUS

convert the polar equation to rectangular form. 1.) r sec(theta) = 3 2.) r = 4 cos(theta) - 4 sin(theta) convert from rectangular equation to polar form. 1.) x^2 + (y-1)^2 = 1 2.) (x-1)^2 + (y+4)^2 = 17

convert the polar equation to rectangular form. 1.) r sec(theta) = 3 2.) r = 4 cos(theta) - 4 sin(theta) convert from rectangular equation to polar form. 1.) x^2 + (y-1)^2 = 1 2.) (x-1)^2 + (y+4)^2 = 17