Unable to plot implicit function in MATLAB 2016a

clc;clear all;close all

syms b P

phi0=asin(1.5/b);

f = -(2*P*1.35/(1.5^2*1.1538*10^5))+...
    ((pi-2*phi0)/(4*sin(phi0)*sin(phi0)))-0.5*cot(phi0);

ezplot(f); grid on

Answer 1

[Star Strider]

You need to make a few changes for this to work:

syms b P

phi0(b) = asin(1.5/b);
P = 2;
f(b) = -(2*P*1.35/(1.5^2*1.1538*10^5))+...
    ((pi-2*phi0(b))/(4*sin(phi0(b))*sin(phi0(b))))-0.5*cot(phi0(b));

ezplot(f(b), [-15 15]); 
grid