Pāṇini sūtras

Also _ta and _ _ tana (before both, on account of the indicatory p the preceding vowel of the verbal stem is strengthened, or if weak not shortened), tana and thana are substituted for the ta of the 2nd Pers. Pl. Imperative in the Veda.

1. tap+tanap+tana+thanāḥतप्+तनप्+तन+थनाः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   tत्	tapतप्	tapतप्	tapतप्	tapतप्
   tत्	tanapतनप्	tanapतनप्	tanapतनप्	tanapतनप्
   tत्	tanaतन	tanaतन	tanaतन	tanतन् + plus aअ
   tत्	thanaथन	thanāḥथनाः	thanaथन	thanथन् + plus āMआM

2. caच

   Part	Lexeme	Sandhi form	Meaning	Stem
   cच्	caच	caच	besides	caच

Anuvṛtti

1. chandasiछन्दसि 7·1·38

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   cच्	chandasछन्दस्	chandasiछन्दसि	Veda	chandछन्द् + plus asiअसि

2. tasyaतस्य 7·1·44

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   tत्	taत	tasyaतस्य	taत	tत् + plus asyaअस्य