1) cosx > -1/17
-arccos(-1/17) < x < arccos(-1/17) + 2πn, n∈Z
-arccos(1/17) < x < arccos(1/17) + 2πn, n∈Z
2) cosx < -1/17
arccos(-1/17) < x < 2π - arccos(-1/17) + 2πn, n∈Z
<span>arccos(1/17) < x < 2π - arccos(1/17) + 2πn, n∈Z</span>
При х= -1
y=2(-1)^3+3(-1)^2+12-1= -2+3+12-1=12
при х=2
y=2*2^3+3*2^2-12*2-1=16+12-24-1=3
Наибольшее при х= -1 y=12
Наименьшее при х=2 у= 3
(х+3)³ - (х+3)² * х + 3(х+3) = 0,
(х+3)((х+3)² - х(х+3) + 3) = 0,
(х+3)(х²+6х+9 - х²-3х + 3) = 0,
(х+3)(3х+12) = 0,
х+3 = 0,
х1 = -3,
3х+12 = 0,
3х = -12,
х2 = -4