- Thread starter
- Admin
- #1
- Feb 14, 2012
- 3,808
If X, Y and Z are in the interval $ (0, \frac{\pi}{2})$, prove that $cosX cosY cosZ+sinXsinYsinZ \leq 1$
Since I see no relevance between X, Y and Z, (but I know I can let X>Y>Z), I don't know how to begin and to be completely candid, I have no clue at all how to do it.
Any hint would be very much welcome.
Thanks.
Since I see no relevance between X, Y and Z, (but I know I can let X>Y>Z), I don't know how to begin and to be completely candid, I have no clue at all how to do it.

Any hint would be very much welcome.
Thanks.