a*F+q=0
with:
F=h1*h2*h3*h4*h5, h1=x-z
h2=cos(2*Pi/5)*x-sin(2*Pi/5)*y-z
h3=cos(4*Pi/5)*x-sin(4*Pi/5)*y-z
h4=cos(6*Pi/5)*x-sin(6*Pi/5)*y-z
h5=cos(8*Pi/5)*x-sin(8*Pi/5)*y-z
q=(1-c*z)*(x^2+y^2-1+r*z^2)^2
r=(1+3*sqrt(5))/4
a=-(8/5)*(1+1/sqrt(5))*sqrt(5-sqrt(5))
c=sqrt(5-sqrt(5))/2
Here is the PoV3-source I used
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