Chapter 2.3, Problem 42ES

In 41-44 a set premises and a conclusion are given. Use the valid argument forms listed in Table 2.3.1 to deduce the conclusion from the premises, giving a reason for each step as in Example 2.3.8, Assume all variables are statement variables.

$p\nu q$

$q\to r$

$p\Lambda s\to t$

~r

$~q\to u\Lambda s$

$\therefore t$