The perfect active stem is formed in what way?

I am clueless, but i think it is removing i from end of the third principal part

Yes, you are right.

For example, in the famous phrase veni, vidi, vici, there are three verbs in their 1st person, singular, present perfect form. If you remove the "i" from the end of each of these, you have the present perfect stem.

=)

Yes, you're on the right track! The perfect active stem of a verb is typically formed by removing the "-i" ending from the third principal part of the verb. The third principal part is usually the perfect active indicative form of the verb.

To find the perfect active stem, you would follow these steps:
1. Find the third principal part of the verb. This is often listed in dictionaries and verb conjugation charts.
2. Remove the "-i" ending from the third principal part.
3. The resulting stem is the perfect active stem of the verb.

For example, let's take the verb "amare" (to love) as an example:
1. The third principal part of "amare" is "amavi" (I have loved).
2. Remove the "-i" ending from "amavi".
3. The perfect active stem of "amare" is "amav-".

So, the perfect active stem of "amare" is "amav-".