deriv SD cv (1287) ashtadhyayi.com hei.de L 1287 ETT STT a 7.2.104 ALPH OLDHOMEPAGE NEWHOMEPAGE

ku tihoH कु तिहोः ONPANINI 72104

Replace /kim with ku कु before a /vibhakti starting with t त् or h ह्.

/tasil and ha ह are /vibhakti by prAgdizovibh... prAgdizovibh...

kim किम् + /Gasi
→ kim किम् + /Gasi
→ kim किम् + tas तस् by paJcamyAstas...
→ ku कु + tas तस् by this rule
→ !**kutaH कुतः "from where?"

ha ह from vAhacacchand...

kim किम् + /Gasi
→ kim किम् + ha ह optionally in the veda by vAhacacchand...
→ kuha कुह by this rule

As in

kim AvarIvaH kuha kasya zarmann ambhaH kim AsId gahanaG gabhIram||
किमावरीवः कुह कस्य शर्मन्नम्भः किमासीद्गहनं गभीरम्॥