Posted by A on Friday, August 12, 2011 at 7:21am.
r=8cos(theta)+5sin(theta), convert the polar equation into a rectangular equation and then complete the square and determine the center radius...?
Help?! I missed the section, and am not getting anywhere with the text...

Trig/precalc  Reiny, Friday, August 12, 2011 at 7:48am
In your text, you should find a diagram similar to this one
http://en.wikipedia.org/wiki/File:Polar_to_cartesian.svg
If you label the endpoint of the rotating arm as either
(x,y) in rectangular and (r,Ø) in polar, then
x = rcosØ or cosØ = x/r
y = rsinØ or sinØ = y/r
also x^2 + y^2 = r^2, and tanØ = y/x
then in your equation r = 8(x/r) + 5(y/r)
multiply by r
r^2 = 8x + 5y
x^2 + y^2 = 8x + 5y
x^2  8x + y^2  5y = 0
This is the equation of a circle. I will assume you know how to complete the square and thus find the centre and radius.
Answer This Question
Related Questions
 PRECALCULUS HELP PLEASE!  convert the polar equation to rectangular form. 1.) ...
 PRECALCULUS  convert the polar equation to rectangular form. 1.) r sec(theta...
 precalculus  convert the equation y^2 = 2x x^2 into polar form. convert the ...
 Precalculus; urgent ! Please help !  1.Graph the polar equation r=32sin(theta...
 PreCalculus  translate this polar equation into a rectangular form: rsin(...
 Pre calculus  in the equation r= 5/(sin theta +2cos theta) the letters r and ...
 PreCalculus  Please check: 1.Find polar equation of x^2 + y^2 = 10y r^2 for x^...
 math  How do I convert the polar equation r  3cos(theta) = 5sin to cartesian ...
 Calculus please help !  1.Graph the polar equation r=32sin(theta) 2. Find the ...
 Math ! Please Help !  1.Graph the polar equation r=32sin(theta) 2. Find the ...
More Related Questions