- Let P(x,y) be the statement “x + y = x - y”, what are true value of "y "x P(x,y) and "x "y P(x,y), where the domain consists of all real numbers?
- Find the argument form for the follow argument and determine wheter it is valid. Can we conclude that the conclusion is true if thepremises are true?
If george does not have eight legs, then he is not an insect.
George is an insect./George has eight legs. - Show pÙ(qÚr) « (pÙq) Ú (pÙr) is a tautology.
- Let P(x,y) be the statement “x2 + y2 = 5”, what are true value of $y $x P(x,y) and $x $y P(x,y), where the domain consists of all real numbers?
- Let P(x,y) be the statement “xy = y”, what are true value of $y "x P(x,y) and "x $y P(x,y), where the domain consists of all real numbers?
這五題是我作業中不會的,我明天就要交了,可是可是可是.......
我到現在還寫不出來 
希望會的人教教我...拜託拜託拜託
