# Real numbers and positive real numbers have same cardinality

How to prove that real numbers and positive real numbers have same cardinality? I know you have to construct a bijective function mapping one to the other. But I have trouble finding this particular function. Thanks!

• $\exp(x)$ works? Jan 28, 2014 at 2:26

$\exp(x)$ works? – janmarqz Jan 28 at 2:26