Conditional Statement for an ode using the time span for plotting the graph

How can i write the code for this conditional statement with respect to the tspan to be used to plot the graph using ode45. gamma is a parameter in the diferential equaltion. tspan=[1 18]

gamma =1 if tspan >=7

and

gamma=0 if tspan >7

[Star Strider]

You posted a duplicate of this question again as how to ascribe two values to a parameter such that it will be time dependent about an hour ago.

That is absolutely not appropriate.

I deleted my answer here.

Good luck!