clear all
close all
clc

Rb=40;
Rmax=45;
NP=100;
for i=1:NP
    R(i)=(i-1)/(NP-1)*(Rmax-Rb)+Rb;
    Af(i)=acos(Rb/R(i));
    B(i)=tan(Af(i))-Af(i);
end
%%
figure('name','Evolvente')
H1=polar(B,R);
set(H1,'LineWidth',2)
grid on