Hi every one, can you help me please !

I have a code about vibration:

function main

d1=1;

v=10;

t_end=100*0.5*d1/v;

t=0:0.0001:t_end;

y0=[0;0;0;0];

[t,y]=ode45(@daodong,t,y0);

hold on;grid on;

plot(t,y(:,1));

xlabel('Thoi gian (s)')

ylabel('Bien Do dao dong (m)')

title('DAO DONG CUA HANH KHACH')

end

function yp = daodong(t,y)

c=10;

vt=10;

k1=84.24;

m1=5.265;

I1=0.2322;

a=0.21;

yp = zeros(4,1);

yp(1) = y(2);

yp(2) = ((-(c*(y(2)-0.05*2*pi*vt*(sin(4*pi*vt*t))-(a*y(4)/2))+k1*(y(1)-(0.05*(sin(2*pi*vt*t))^2)-(a*y(3)/2))))/m1);

yp(3) = y(4);

yp(4) = ((-(a*c*(y(2)-0.05*2*pi*vt*(sin(4*pi*vt*t))-(a*y(4)/2))+a*k1*(y(1)-(0.05*(sin(2*pi*vt*t))^2)-(a*y(3)/2))))/(2*I1));

end

Can you help me draw graph "Amplitude - Frequency"draw graph "Amplitude - Frequency" of y(:,1), please!

Thank you very much every one.

[darova]

The script works fine as for me