A conjunction means each part must be true for the whole statement to be true. Let's break it down into atoms again. Lots of numbers are less than 4. Next. Not(*x*^{2} < 20) is a negation of whatever is inside the parentheses. So the negation of "*x*^{2} is less than 20" would be "*x*^{2} is not less than 20" or "*x*^{2} is greater than or equal to 20." For the entire statement to be true, we need a number that is less than four but greater than 20 when squared. Does such a number exist? You betcha. If we make *x* = -5, it satisfies both atoms in the statement, and therefore makes the whole statement true. |