How to give a piecewise function as input

clear all

clc

syms t s y(t) Y

dy(t)=diff(y(t));

d2y(t)=diff(y(t),2);

F = input('Input the coefficients [a,b,c]: ');

a=F(1);b=F(2);c=F(3);

nh = input('Enter the non-homogenous part f(x): ');

eqn=a*d2y(t)+b*dy(t)+c*y(t)-nh;

LTY=laplace(eqn,t,s);

IC = input('Enter the initial conditions in the form [y0,Dy(0)]: ');

y0=IC(1);

dy0=IC(2);

LTY=subs(LTY,{laplace(y(t), t, s),y(0),dy(0)},{Y,y0,dy0});

eq=collect(LTY,Y);

Y=simplify(solve(eq,Y));

yt=simplify(ilaplace(Y,s,t));

disp('The solution of the differential equation y(t)=')

disp(yt);

lhs input:

[1,0,16]

rhs input:

F(t)=cos4t 0<t<pi

o t>pi

Answer 1

[Robert U]

Hi Mehul kumar,

Please, have a look here: https://de.mathworks.com/matlabcentral/answers/359268-making-ramp-and-unit-step-function-in-matlab?s_tid=srchtitle

Kind regards,

Robert

Answer 2

[VBBV]

clear all
clc
syms t s y(t) Y
dy(t)=diff(y(t));
d2y(t)=diff(y(t),2);
F = [-1 1 16]; %input('Input the coefficients [a,b,c]: ');
a=F(1);b=F(2);c=F(3);
nh = piecewise(t>0 & t< pi, cos(4*t), 0) %input('Enter the non-homogenous part f(x): ');

nh = 

eqn1=a*d2y(t)+b*dy(t)+c*y(t)-subs(nh,t,0)

eqn1 = 

eqn2=a*d2y(t)+b*dy(t)+c*y(t)-subs(nh,t,pi)

eqn2 = 

% LTY=laplace([eqn1 eqn2],t,s)
IC = [y(0) == 1; dy(0) == 0];% input('Enter the initial conditions in the form [y0,Dy(0)]: ');
y0=IC(1);
dy0=IC(2);
% LTY=subs(LTY,[laplace(y(t), t, s),y(0),dy(0)],[Y,y0,dy0])
% eq=collect(LTY,Y)

sol =simplify(dsolve([eqn1 eqn2],IC));
% yt=simplify(ilaplace(y,s,t))
disp('The solution of the differential equation y(t)=')

The solution of the differential equation y(t)=

disp(sol)

fplot(sol,[-1 1])