f(x) "Hot Summer" Song

f(x) (Korean: 에프엑스; pronounced /ˌɛf ˈɛks/) is a five member South Korean girl group formed by SM Entertainment in 2009. The name is a play on the mathematical notation for function, with "f" signifying "flower" and "x" representing the female's double X chromosome. The group members have also been nicknamed "function girls". The group made their debut on September 1, 2009 with release of a