How to create equation with time instant in simulink work space

hello everyone

if i have this simulink module; and Sn is the output from subtract block how i can create these equation in the output

if n is considered a time ; for example Sn at n=4sec , then n-1=3sec and n-2=2sec so on , i want Delta valve in each time instants

Answer 1

[Jim Riggs]

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