Using ODE45 for first order diff equation with three different variables

So, I am trying to use ODE45,

say dx/dt = (0.1*x)+(0.25*y)-(9.8*z)

I am trying to graph the behavior of x,y and z from time (0 to 100). What should i do to set up as in funciton file?

i tried

function dxdt = func(t,x,y,z)
dxdt = (0.1*x)+(0.25*y)-(g*z);
end

%main script
tspan = [0 100];
xint = 0;
yint = 0;
zint = 0;
[t,x,y,z] = ode45(func,tspan,xint,yint,zint);

But after i run this code i am getting an error says not enough input arguments.I am still adpoting the concept of using ode function but Please help!

I need to plot x,y,z from 0 to 100

[Wan Ji]

Hi, you should have three equations for solving ode of x,y,z with respect to t. But you only provided one

Answer 1

[Wan Ji]

For example

function dxdt = func(t,x,g)
dxdt = zeros(3,1);
dxdt(1) = (0.1*x(1))+(0.25*x(2))-(g*x(3));
dxdt(2) = (0.1*x(1))+(0.25*x(2))-(g*x(3));
dxdt(3) = (0.1*x(1))+(0.25*x(2))-(g*x(3));
end

The main function

tspan = [0 100];
g = 10;
[t,x] = ode45(@(t,x)func(t,x,g),[0,100],[0;0;0]);
xsol = x(:,1);
ysol = x(:,2);
zsol = z(:,3);