आद्यन्तौ टकितौ

This sutra explains the special use of two of the indicatory letters ट् and क्. Where the indicatory letter of an augment is ट् that augment is to be placed before the word in the genitive case with regard to which it is enjoined; while a कित् augment is to be added after the word exhibited in the 6th case with regard to which it is enjoined. Thus, there is a sutra 7.2.35 which says \ardhadhatuka affixes beginning with a consonant except य, have इट्\. The question may arise where is this इट् to be added, in the beginning or the end or the middle of the ardhadhatuka affix? This sutra answers the question. The indicatory ट् shows, that it is to be placed before the ardhadhatuka affix. Thus the future termination स्यति, is an ardhadhatuka affix: when this is added to the root, it takes the augment इट्. Thus भू + इट् + स्यति = भविष्यति, 'he will be.' Similarly लविता 'he will cut'.

Similarly by sutra (VII. 3. 40.) the root भी takes the augment षुक् in forming the causative. This having an indicatory क् is to be added after the word भी, as, भी + षुक् + णिच् + त = भीषयते 'he frightens.',