Question Summary:
Mistake in salah

Question Detail:

I joined asr salaah late..it was second rakaat but i without realizing it stood up instead of sitting in attaiyait..now wat should i do..should i have sit back and perform sajdah sahw or continue with saalah

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
 
If you joined the Imam in the second rak’ah, and you mistakenly stood up for the third rak’ah when the Imam sat in attahiyyat, you have to return and join the Imam. Since you made a mistake while performing salah with the Imam, their is no Sajdah sahw. [1] Make tawbah and istighfar for not diligently following the Imam.
 
And Allah Ta’āla Knows Best
Zakariya Memon
Student Darul Iftaa
Chatham, Canada 
Checked and Approved by,
Mufti Ebrahim Desai.
Daruliftaa.net