Answer: Suppose we send out our newest "tweet" to our 5000 Twitter followers.
If 10 followers have seen the tweet after 1 minute, then the differential equation can be written as ;
Let us first assume that at time "t" , "n" followers have seen this tweet.
So, no. of follower who have not seen this tweet are given as : 5000 - n
ratio = [tex]\frac{n}{5000 - n}[/tex]
∴ we get ,
[tex]\frac{\delta x}{\delta t}[/tex] ∝ [tex]\frac{n}{5000 - n}[/tex]
[tex]\frac{\delta x}{\delta t}[/tex] = k×[tex]\frac{n}{5000 - n}[/tex] ------ (1)
where k is the proportionality constant
At t = 0 , one follower has seen the tweet.
So n(0) = 0 ------ (2)
So n(1) = 10 ------ (3)
∴ equation (1), (2) and (3) together model the no. of followers that have seen the tweet.