Inside your function you are calling your function.You are also redefining the parameters you are sending to your function Vo, t inside the function
There might be more efficient ways but one way you could do this is take the for loop out of the function and your function would compute and plot x and y every call
function [x , y] = trajectory(Vo,O,t,g)
% Function for varying angle
x = Vo * cos(O) * t ;
y = Vo*(sin(O)*t)-(0.5*g*(t.^2));
plot (x,y);
hold on
end
then in order to call this function use
for O = (0: (pi/8): pi);
[x,y] = trajectory(10,O,[0:1:5],9.8);
end
if you want to keep that loop inside the function and just have a function call
function [x , y] = trajectory(Vo,t,g)
% Function for varying angle
for O = (0: (pi/8): pi);
x = Vo * cos(O) * t ;
y = Vo*(sin(O)*t)-(0.5*g*(t.^2));
plot (x,y);
hold on
end
end
and to call it would be
[x,y] = trajectory(10,[0:1:5],9.8);
