First of all, I am not sure if vectors are pre-calculus topics! If they are can any moderator please move this topic, I'm sorry for the inconvenience.

Any way,

By vector I mean the arrow above the variable. I really do not have a clue how to solve this, I tried many things but all failed, so I checked the given solution by the text book and found it a bit unusual to my taste ( if that makes sense). How would you solve this question?In triangle ABC, a median is drawn from vertex A to the midpoint of BC, which is labelled D. If vector AB = vector b and vector AC = vector c, prove that vector AD = 1/2 vector b + 1/2 vector c.

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