clear
a1=0.1031;
d1=0.4;
m1=16.18;
x=4:0.1:7;
y=x.^0.5;
p1=a1*pi*m1;
t1=(2*pi*m1).y;
alfa1=-d1-(p1./y).*cos(t1);
plot(x,alfa1);
grid