How do you convert 4y+2=(3x+4)^2+(2y-1)^24y+2=(3x+4)2+(2y1)2 into polar form?

1 Answer
Apr 15, 2018

See below

Explanation:

The conversion from Rectangular to Polar:
x=rcosthetax=rcosθ
y=rsinthetay=rsinθ

Substitute for xx and yy and solve for rr:
4(rsintheta)+2= (3(rcostheta)+4)^2+(2(rsintheta)-1)^24(rsinθ)+2=(3(rcosθ)+4)2+(2(rsinθ)1)2

4rsintheta+2= (3rcostheta+4)^2+(2rsintheta-1)^24rsinθ+2=(3rcosθ+4)2+(2rsinθ1)2

4rsintheta+2= 9r^2cos^2theta+24rcostheta+16+4r^2sin^2theta-4rsintheta+14rsinθ+2=9r2cos2θ+24rcosθ+16+4r2sin2θ4rsinθ+1

9r^2cos^2theta+24rcostheta+4r^2sin^2theta-8rsintheta+15=09r2cos2θ+24rcosθ+4r2sin2θ8rsinθ+15=0

r(9rcos^2theta+24costheta+4rsin^2theta-8sintheta)=-15r(9rcos2θ+24cosθ+4rsin2θ8sinθ)=15

At this point either rr is equal to -1515 or (9rcos^2theta+24costheta+4rsin^2theta-8sintheta)=-15(9rcos2θ+24cosθ+4rsin2θ8sinθ)=15

Let's solve the second:
9rcos^2theta+4rsin^2theta=8sintheta-24costheta-159rcos2θ+4rsin2θ=8sinθ24cosθ15

r(9cos^2theta+4sin^2theta)=8sintheta-24costheta-15r(9cos2θ+4sin2θ)=8sinθ24cosθ15

r=(8sintheta-24costheta-15)/(9cos^2theta+4sin^2theta)r=8sinθ24cosθ159cos2θ+4sin2θ