Question

convert r=2sin(theta)-4cos(theta) to a rectangular equation

Answer 1

r=2sin(theta)-4cos(theta)
cos theta =x/r, and sin(theta) = y/r
r^2 =x^2+y^2
r= 2(x/r)-4(y/r)
r^2 =2x-4y
x^2+y^2 =2x-4y
x^2-y^2-2x+4y=0

Source: http://www.mathskey.com/question2answer/ask

Answer 2

Please see example problem here.
http://www.mathskey.com/question2answer/16710/identify-the-graph-of-r-4-cos-theta-4-sin-theta

Answer 3

r^2=x^2+y^2
x=r cosθ → x/r=cosθ→ x/\(\sqrt(x2+y\)2)=cosθ
y=r sinθ → y/r=sinθ→ y/\(\sqrt (x2+y2)\) =sinθ