Cant take the derivative of this plot...

clc
clear
m = 1;
b = 2;
k = 10;
t = linspace(0,7,175);
xlabel('0');
syms s
F=1./(m*s.^(3)+b*s.^(2)+k*s);
f=ilaplace(F,t);
plot(t,f)
xlabel('Time (t)')
ylabel('Displacement x(t)')

I have this code that gives a nice oscillating plot. But, I need to take the derivative of this plot and plot that as well.

[Walter Roberson]

See gradient

[Peter Fennell]

Thank you!

Answer 1

[Torsten]

m = 1;
b = 2;
k = 10;
tnum = linspace(0,7,175);
xlabel('0');
syms s
F=1/(m*s^3+b*s^2+k*s);
f=ilaplace(F);
df=diff(f);
varf = symvar(f);
vardf = symvar(df);
plot(tnum,double(subs(f,varf,tnum)))
xlabel('Time (t)')
ylabel('Displacement x(t)')

plot(tnum,double(subs(df,vardf,tnum)))
xlabel('Time (t)')
ylabel('Velocity u(t)')