after every 9th visit to a restaurant you receive a free beverage after every 12th visit you receive a free appetizer if you vis
1 answer:
You might be interested in
Not sure why such an old question is showing up on my feed...
Anyway, let
and 
. Then we want to find the exact value of 
.
Use the angle difference identity:
and right away we find
. By the Pythagorean theorem, we also find 
. (Actually, this could potentially be negative, but let's assume all angles are in the first quadrant for convenience.)
Meanwhile, if
, then (by Pythagorean theorem) 
, so 
. And from this, 
.
So,
Anyway, let
Use the angle difference identity:
and right away we find
Meanwhile, if
So,