Mistakenly sitting after the first rakaat
Q:
1. If the Imaam in taraweeh salaah mistakenly sits down for tashahhud after one rakaat, thinking it to be the second rakaat. After sitting down, he immediately realized and stood up for the second rakaat. In such a case, will he have to make sajdah sahw?
2. And what about if this happens in farz Salaah?