r = 0.001:0.001:3; % some r values
mu = 1; % some mu value (could be a vector the same size as r)
x = zeros(size(r));
y = -0.125.*r + 1.125./r;
z = 1./mu.*(1.25.*r.^2+9.103.*log(r)+1.296)-0.5.*log(r);
figure
plot3(x,y,z)
xlabel('x')
ylabel('y')
zlabel('z')
% or perhaps
figure
plot(y,z)
xlabel('y')
ylabel('z')
