Use mathematical induction to prove the product rule for m tasks from the product rule for two tasks. I'm not exactly sure how to do this using mathematical induction. Thanks for the help. 
I'm trying to prove that the product rule is valid for some number of tasks $m$, such that $m$ is greater than two using induction and the product rule for two tasks as a given. 
The product rule for a two-tasks procedure states that, there are $n_1n_2$ ways to do a procedure, when there are $n_1$ ways to do the first task and for each of these ways of doing the first task, there are $n_2$ ways to do the second task

Hint:  Suppose you know that for a $(k-1)$-task procedure, there are $n_1 n_2 \cdots n_{k-1}$ ways to do the procedure.  And that there are $n_k$ ways to do a $k$-th task.  Then what does the product for two-task procedures tell you for the number of ways to do the two-task procedure: (1) perform the $(k-1)$-task procedure; (2) then perform the $k$-th task.
