We would need the info about the lengths of the sides of said polygon.
Once your friend has thought of a number, do the following:
1. Ask him or her to multiply the chosen number by 2.
2.Choose an even number to use yourself. Ask your friend to add this number to the one in his head.
3.Tell him/her to divide the new number by 2.
4.Tell your friend to subtract his original number from the equation.
5."Guess" the number.
:)
As it stands, it's none of those. I believe you were going for the distance formula but copied it wrong.
d(x) = { (x,y): y = sqrt(x) and y >=0 }
since sqrt function requires x to be >=0 so
<u>x >= 0</u>
