K-Pop I LOVE YOU: F(x)

f(x) ( Band)
에프엑스) 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, and when input with different 'x', there can be many different outcomes. f(x) strives to be the kind of girl group that can change and adapt to many situations. The group members have also been nicknamed "function girls". The group made their debut on September 1, 2009 with release of a digital single "La Cha Ta" (stylized as "LA chA TA"). The quintet consists of Victoria, Amber, Luna, Sulli and Krystal.

Pre-debut history Krystal Jung was first spotted by SM Entertainment in 2000 on a family visit to Korea, which earned her a small role in a short segment of Shinhwa's "Wedding March" music video. Sulli Choi first debuted as a child actress in 2005 when she was selected to play young Princess Sun-hwa in the SBS television drama, The Ballad of Seo-dong.^[2] In 2006, SM Entertainment recruited Luna after seeing her performing on SBS's television program, "Truth Game".^[3] Victoria was spotted by a S.M. Entertainment's agent at a Beijing dance competition, and later joined the company. Two months later, Amber was cast through SM's Global Auditions in Los Angeles, California, where she was one of two people (one male) selected to be trainees.

2009: Debut, first single album and collaborations

SM first released a teaser preview of the group via YouTube on August 24, introducing them as "Asia's Pop Dance Group." For five days, SM individually released information through news portals and posted pictures of each member on SM Town's official website, starting with Korean member Sulli on August 26, Taiwanese-American member Amber on August 27, Korean-American member Krystal on August 28, Korean member Luna on August 29, and lastly the Chinese member Victoria on August 30.
On September 1, the group's first single "La Cha Ta" (stylized as "LA chA TA") was digitally released. Following their first performance at the Samseong-dong Fashion Center on September 2, the music video was screened and released online the next day. The group's first broadcast performance of "La Cha Ta" was held at MBC's music show Show! Music Core on September 5.
On October 7, the group also released the electro-pop version of the digital single, "Chocolate Love", alongside their label mate Girls' Generation.^[4] The single was released for the promotion of the 4th edition Blacklabel series of LG CYON phone, LG Chocolate (BL40).
On November 9, f(x) released their first single album, Chu~♡, consisting of 3 songs.
On December 19 and 20, f(x) appeared as special guests on Into the New World concert of their label-mate girl group, Girls' Generation, in Olympic Fencing Gymnasium.
f(x) La Cha Ta