Question

Need help finding if a proposition is a tautology.

Answer 1

I just need help with part B

Answer 2

If a proposition is a tautology, that means every value in the truth table is going to yield you T. If you have one value of the proposition be F, then it is definitely not a tautology.

Make a truth table for the original proposition ( P => Q ), converse ( Q => P ), and its contrapositive ( not Q => not P ).

Answer 3

The problem I have is I don't know how to make a truth table for rounded E

Answer 4

I know it means "in" but how would I get the truth value for x in A?

Answer 5

If x is in A, that means x is an element that is part of set A. If x is ACTUALLY an element of set A, then the value in the truth table will be T.
So if the set is A: { multiples of 4 }
and
x = 5
it would be false, since it is false that x is an element of the set of multiples of 4.

Answer 6

x A x in A
T T T
T F F
F T F
F F F

Answer 7

so would that be correct?