Algebra 1: Spreading Doom

Students are presented with a scenario about a computer virus named Mydoom which infected millions of computers in 2004. Students will derive an equation to model the spread of Mydoom.

Students use ListEditor to assist them in their investigation. L1 gives the number of hours since the virus was released. L2 gives the number of emails sent by the virus in that hour.

Using the number of emails sent by Mydoom each hour students form a geometric sequence. They should see that in this type of sequence there is a fixed number called the common ratio.

After determining their sequence and a rule, students find the next few terms. They enter their rule in L2(5) and use L2(4) to represent the previous entry in the list and multiply by 1.8. Students repeat the process until they have found the first ten terms.

They then create a scatter plot of the data. Students discuss which variable is dependent or independent and the shape of the scatter plot.