S=u*t
u=70км/ч = 70*1000/3600= 19,45м/с
t=60+12=72сек
s=72*19.45= 1400 метров
Sinx=a ⇒ x=(-1)^n*arcsina+πn
a=√2/2 x=(-1)^n*π/4+πn n∈Z
(x² + 3x) /8 - x / 2 = 0
(x² + 3x) /8 = x / 2
8x = 2( x² + 3x)
8x = 2x² + 6x
8x - 2x² - 6x = 0
- 2x² + 2x = 0
2x² - 2x = 0
D = b² - 4ac = (-2)² - 4 × 2 × 0 = 4 = 2²
x₁ = 2 + 2 / 4 = 4/4 = 1
x₂ = 2 - 2 / 4 = 0 / 4 = 0