[44-4] exercise designed to employ cp twice to get an
equivalence
*. 1st proof for a -> b by cp
*. 2nd proof for b -> a by cp
*. combine them by conj
*. then use equiv
c: a < -> b
1: a -> ~c
2: ~b -> c
3: a v ~b

a function could be identified in 3 ways either on a chart,graph, or ordered pairs. first a function is that each point has its own. the rule is that there can be many x's to one y but there can not be 2 x's at different y's. so on a graph when you put a straight line through the y's there should be one dot only to be a function.

step-by-step explanation: