Question

I need help with Computer Science! Can someone help?

Answer 1

!((x>y)||(y <= 0)) is equivalent to which of the following expressions?
I !(x>y)|| !<=0)
II !(x>y) &&! (y <=0)
III(x<=y) && (y>0)

Answer 2

the ! symbol represents a 'flip'.
```
boolean a = !true; //this says a = (flip)true; so a = false;
```
Your question pertains to the logic of:
```
!((x>y)||(y <= 0))
```
I'm sure you're already aware of less than / greater than / less than and equal to operators (operators perform operations on pieces of data.. + - * and / are examples of operators) the || operator translates to 'or'.. so within logic, doing:
```
int x = 5;
int y = 7;
if(y < x || x <= 5) { //this will execute if the statement in parenthesis is true }
```
In english, that if statement is if y is less than x OR if x is less than or equal to 5, then this statement is true. It happens that x is less than or equal to 5, so the entire statement is true.

There is an && operator, also called an and operator. This is only true when both logic segments are true.
```
int x = 5;
int y = 7;
if(y < x && x <= 5) { //this will execute if the statement in parenthesis is true }
```
In this case, it isn't true, because both sides of the && would have to be true in order for the statement to be true. X would have to be greater than y and x would have to be less than or equal to 5.

Back to your question - I'll write down the logic of what
```
!((x>y)||(y <= 0))
```
says, and then you can write out the logic of the 3 answers. It's a good practice to write out the logic.

Note that there are parenthesis around the entire logic statement.. remember that ! flips the outcome.. so whatever the outcome (true/false) of
```
(x > y) || (y <= 0)
```
is going to become the opposite when the ! is added outside of the parenthesis. I'm sure you're familiar with pemdas -- kind of the same thing here, whatever is in parenthesis will execute first.
```
!((x > y) || (y <= 0)) //outcome will be flipped
```
logic: (opposite of) (if x is greater than y OR y is less than or equal to 0).

Answer 3

ok I see, so it would only be the first problem?

Answer 4

I've provided the tools for you to figure out the answer to the question - now it's up to you to figure it out.

Answer 5

oh ok, thank you.

Answer 6

Sure