What should the worshiper do if he discovers that he recited the Tashahhud instead of the Fatihah in the last rak'ah of the 'Asr prayer, then bowed with the Imam before he was able to recite the Fatihah?

Reciting Al-Fatiha is obligatory in prayer. The majority of scholars hold that it is obligatory for the worshipper praying behind an Imam (ma'mum) in a silent prayer. Imam Malik differed, considering it merely recommended. Meanwhile, the Hanafis believe that the ma'mum should not recite anything behind the Imam, neither in silent nor in audible prayers. Based on the fact that the questioner did not intentionally omit reciting Al-Fatiha, but rather recited something else by mistake and was unable to recite it afterwards, her prayer is valid and nothing is incumbent upon her.