Question

Assuming a is a bool with a value of false, which of the following evaluates to true?

-!(!a)
-a
-!a
-None of the above.

Answer 1

When 'a' is false, both '!(!a)' and '!a' evaluate to true due to the rules of boolean logic. The negation operator '!' flips the truth value, so the double negation in the first case and a single negation in the third result in a value of true.

Step-by-step explanation:

The question you've asked is rooted in boolean logic, which is integral to computer science and programming. So, let's explain the correct answer based on the value of 'a' being false:

1. !(!a) - This one is true. The inner negation turns 'false' into 'true', and the outer negation flips it back to 'false', so when you negate again, it becomes 'true'.
2. a - This one is false, because the value of 'a' has been given as false.
3. !a - This is true. The negation of a 'false' value is 'true'.

Conclusion: The expressions that evaluate to true when 'a' is false are !(!a) and !a.