Truth table and proving a tautology

In summary, the conversation is about proving a statement to be a tautology using a truth table. The attempt at solving the problem is shown, but it is determined that there is a mistake in the expression or the exercise is worded incorrectly.
  • #1
arnold28
14
0

Homework Statement


I'm supposed to prove that this statement is a tautology (with truth table):

(p -> ((p OR q) AND ~q)) = (~p OR ~q) AND p


Homework Equations





The Attempt at a Solution



Code:
p | q | ~p | ~q | p OR q | (p OR q) AND ~q | p -> ((p OR q) AND ~q) | (~p OR ~q) | (~p OR ~q) AND p
----------------------------------------------------------------------------------------------------
1   1    0    0      1            0                      0                 0               0
1   0    0    1      1            1                      1                 1               1
0   1    1    0      1            0                      1                 1               0
0   0    1    1      0            0                      1                 1               0

But here cleary is that it is not tautology, because left side of equation gets 0 1 1 1 and right side 0 1 0 0

So where did i make mistake, because i can't see it
 
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  • #2
Are you sure you have the parentheses right in the expression that is to be proven?
 
  • #3
yes, it is just like that in the excercise paper
 
  • #4
so do you think that I have done it right and the excercise is badly worded?
 

FAQ: Truth table and proving a tautology

What is a truth table?

A truth table is a visual representation of all possible combinations of truth values for a logical statement. It shows the resulting truth values of the statement for each combination of truth values for its individual components.

How do you create a truth table?

To create a truth table, you first list all the individual components of the logical statement. Then, you create columns for each component and the resulting truth value. Finally, you fill in the truth values for each combination of the component values, starting with all false values and working your way up to all true values.

What is a tautology?

A tautology is a logical statement that is always true, regardless of the truth values of its components. In other words, it is a statement that is true in all possible scenarios.

How do you prove a tautology?

To prove a tautology, you can use a truth table to show that the statement is true for all possible combinations of truth values for its components. Another method is to use logical equivalences to simplify the statement and show that it reduces to a known tautology, such as "p OR NOT p".

Why is proving a tautology important in science?

In science, proving a tautology can help validate a hypothesis or theory by showing that it is logically sound and always true. It also allows for the identification of any errors in the reasoning or assumptions made in the statement. Additionally, tautologies are often used in the construction of mathematical proofs, which are essential in many scientific disciplines.

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