Skrytý text:

is ACUTE-angled triangle, then

. Function

is convex

and

and

. So, for

from Jensen inequality we get

.
Function

is convex

, because

. So, from Jensen inequality we get

. From

and

we get

.
Edit: Let

be equilateral, then

. So


is right-angled triangle,

is non define.

is obtuse-angled triangle,

,

a

.
For

:

. So

and

. From

we get

.

If

is even then

and

then

, because

is rising -it doesn t have minimum.

If

is odd, then

,
http://www.wolframalpha.com/input/?i=mi … *x%29%29^n then it doesn t have minimum.
EDIT: Thanks to check_drummer for his advice.:)