# Pars a fluctuating parameter in an ODE

Dear Julia users,

I am new to julia and I want to solve an ODE system with some fluctuating parameters.
Let say that I have a fluctuating temperature T as function of time:

``````T = 18
time = collect(0:0.01:365)
vecT = T.+0.2*T*sin.((1/10)*2*pi.*time);
fig, ax=PyPlot.subplots(figsize=(8,2))
ax.plot(vecT)
``````

Let say I have a parameter that is a funciton of T in my ODE. How can I implement it?

``````# The ode model
function dudt(u,p,t)
a = p[1];
b = p[2];
μ  = a*exp(-b/T(t))
ψ  = p[3];

return μ-ψ
end
``````

Just define `f(t) = T.+0.2*T*sin.((1/10)*2*pi.*t)` and then use it inside of your ODE