r=thetacos((7pi)/4-3theta)
color(blue)(d/(d(theta)))r=color(blue)(d/(d(theta)))(thetacos((7pi)/4-3theta)
(dr)/(d(theta))=cos((7pi)/4-3theta)+3thetasin((7pi)/4-3theta)
cos((7pi)/4-3((-2pi)/3))+3((-2pi)/3)sin((7pi)/4-3((-2pi)/3))
cos((7pi)/4+2pi)-2pisin((7pi)/4+2pi)
cos((7pi)/4)-2pisin((7pi)/4)
sqrt2/2-2pi*-sqrt2/2
((1+2pi)sqrt2)/2