Homepage › Solution manuals › Terence Tao › Analysis I › Exercise 5.4.1 (Basic properties of positive reals)
Exercise 5.4.1 (Basic properties of positive reals)
Prove Proposition 5.4.4.
Proposition 5.4.4. For every real number , exactly one of the following three statements is true: (a) is zero; (b) is positive; (c) is negative. A real number is negative if and only if is positive. If and are positive, then so are and .