<span>Решите неравенство :x^2-2x-15больше или равно 0
</span>Ответ: больше 0
а)
2sin²x-3√2cos(3π/2+x)+2=0
2sin²x-3√2sinx+2=0
D=18-16=2
(sinx)₁=(3√2-√2)/4=√2/2 ⇒ x=π/4+2πk; x=3π/4+2πk; k∈Z
(sinx)₂=(3√2+√2)/4=√2 ∉ [-1; 1] ⇒ ∅
б)
3π/4+2π=11π/4 ∈ [5π/2; 4π]
x=π/4+2πk ∉ [5π/2; 4π]
Ответ: а) x=π/4+2πk; x=3π/4+2πk; k∈Z, б) 11π/4
4t - 1 = 0
4t = 1
t = 1/4
t = 0,25
8t - 3 = 0
8t = 3
t = 3/8
t = 0,375
12t - 17 = 0
12t = 17
t = 17/12
t = 1 целая 5/12
1) 45:100*3=1,35
2) 12:100*125=15
3) 15:100*2=0,3
4) 250:100*206=515