How do you convert r = 5 cos (t)r=5cos(t) to rectangular form?

1 Answer
Mar 3, 2016

r=5cost->r*r=r*5cost->r^2=5rcost->x^2+y^2=5x->x^2-5x+y^2=0->(x-5/2)^2+y^2=25/4r=5costrr=r5costr2=5rcostx2+y2=5xx25x+y2=0(x52)2+y2=254

Explanation:

Multiply both sides by r then use the formula r^2=x^2+y^2, x=rcosthetar2=x2+y2,x=rcosθ to change from polar to rectangular. Put everything on one side and complete the square to find the answer.