Show that 
is increasing on 
.
Consider 
in 
cos>0,
tan x-x>0,
sin2x>0
hence f’(x)>0,
so, function is increasing in the given interval.
1
Show that is increasing on .
Consider
in cos>0,
tan x-x>0,
sin2x>0
hence f’(x)>0,
so, function is increasing in the given interval.