Plot Equation to 3d

how to plot this function as 3d in matlab? I have tried ezplot and fplot functions, but they are not working for. Any suggestion will be quiet helpful. I want to plot the values of A, phi and R on 3d-graph. thankyou

Answer 1

[KSSV]

N = 50 ;
B = rand ;   % a constant 
a =linspace(0,4,N) ;
phi = linspace(0,2,N)*pi/180 ;
[A, Phi] = meshgrid(a,phi) ;

R = A.*sin(Phi/2)./(B*cos(Phi/2).^2) ;

surf(A,Phi,R)