how to compute derivative

having all the values in the above equation, is the below code correct for dE(t)/d(t) computation?

dEt = beta * (1 - sigma) * St * It - (mu + alpha) * Et

what do i need to do to compute dE(t)/d(t)

[darova]

Looks like differential equation. DO you have initial value ?

You can use ode45

[Elysi Cochin]

i too saw ode45 to solve differential equation,

i have all values, but i dont know, how to pass this equation to ode45?

[darova]

Do you have any attempts?

[John D'Errico]

What you have not said is explicitly WHAT you have.

What does it mean to have values?

is beta a fixed known constant? How about mu and alpha?

Is S known as a function, or do you have a list of points for S as a function of t?

Similarly for I(t). Is that known?

Is E(t) known, or are you trying to solve for E(t). That would make this a differential equation, if E is an unknown function.

Finally, do you have some sort of initial value for E(t) at some fixed value for t?

Answer 1

[darova]

Only you know initial conditions. Imagine the situation: you are throwing the ball, initial conditions are velocity and angle. Only you know how you want to throw the ball

YOu should use for loop to get solution for all your values

for i = 1:size(SIE,1)       % numer of rows
    S = SIE(i,1);
    I = SIE(i,2);
    E = SIE(i,3);
    [t,E] = ode45(@(t,E) myfunc(t,S,I,E),tspan,E);
    line(t,E)
end

[Elysi Cochin]

why do i get 10 curves? shouldnt it be one curve? how to get one curve? is it possible with the equation and datas above?

[darova]

One curve for one set of data. You can't get one curve if you have many values and initial conditions, it's impossible

Imagine you are throwing the bal at different angles but want to get only want trajectory

One angle - one trajectory