4 senx cosx+1 ≤ 0
4 senx cosx+1 ≤ 0
Ciao.
4·SIN(x)·COS(x) + 1 ≤ 0
2·SIN(2·x) + 1 ≤ 0
SIN(2·x) ≤ - 1/2
pi + pi/6 ≤ 2·x ≤ 2·pi - pi/6
7·pi/6 ≤ 2·x ≤ 11·pi/6
7·pi/6 + 2·k·pi ≤ 2·x ≤ 11·pi/6 + 2·k·pi
pi·(12·k + 7)/12 ≤ x ≤ pi·(12·k + 11)/12
Questa é riconducibile ad elementare
2 sin 2x <= -1
sin 2x <= -1/2
7/6 pi + 2k pi<= 2x <= 11/6 pi + 2k pi
7/12 pi + k pi <= x <= 11/12 pi + k pi, k in Z