# How to marker a fplot(anonymous function) function on a specific point which user enters.

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Khashayar Asadi on 24 Aug 2021
Commented: Khashayar Asadi on 24 Aug 2021
Hello, I wrote a function which needs a (t) as input and it graphs something i want to marker the point which user inputs on the graph for example if user defines t=10 I want to marker the graph on point t=10 and x(t)=10. how should I do that. here is my code
function x=calcDisplacement(t)
m=1100;
k=570;
c=430;
x0=0.05;
v0=0;
omega_d = sqrt((4*m*k)-(c^2))/(2*m);
sigma = c/(2*m);
alpha = x0/2;
beta = -((v0+x0)/(2*(omega_d)));
displacement=@(t) 2*exp(-2*(sigma).*t).*(((alpha)*cos((omega_d).*t))-(beta)*sin((omega_d).*t));
x=displacement(t);
fplot(displacement,[0 50],'color','blue')
ylim([-0.1 0.1])
legend ('Displacement of suspension')
ylabel('Displacement(m)')
xlabel('Time(s)')
title('Graph of displacement in car suspension')
hold on;
end

Turlough Hughes on 24 Aug 2021
Edited: Turlough Hughes on 24 Aug 2021
You can add it in at the end of your function using plot:
function x=calcDisplacement(t)
m=1100;
k=570;
c=430;
x0=0.05;
v0=0;
omega_d = sqrt((4*m*k)-(c^2))/(2*m);
sigma = c/(2*m);
alpha = x0/2;
beta = -((v0+x0)/(2*(omega_d)));
displacement=@(t) 2*exp(-2*(sigma).*t).*(((alpha)*cos((omega_d).*t))-(beta)*sin((omega_d).*t));
x=displacement(t);
fplot(displacement,[0 50],'color','blue')
ylim([-0.1 0.1])
ylabel('Displacement(m)')
xlabel('Time(s)')
title('Graph of displacement in car suspension')
hold on;
plot(t,x,'ok','LineWidth',2)
legend ('Displacement of suspension','point of interest')
end
Khashayar Asadi on 24 Aug 2021
Thank you. Really helped me.