В) <span>.
2*{[cos(x + 3x)/2] * [cos(x - 3x)/2]}= cos2x
2*[cos2x*cosx] - cos2x = 0
cos2x(2cosx - 1) = 0
1) cos2x = 0
2x = </span>π/2 + πn, n∈Z
<span>x1 = </span>π/4 + (πn)/2, n ∈Z
<span>2) 2cosx - 1 = 0
cosx = 1/2
x = (+ -) arccos(1/2) + 2</span>πk, k∈Z
<span>x2 = (+ -)*(</span>π/3) + 2πk, k∈Z <span>
</span>
V(класса) = 7 * 5 * 3 =105 (м³)
На одного ученика приходится :
105/25 = 4.2 (м³)
x|y
-3|5⁻³⁺¹=5⁻²=1/25 (-3;1/25)
-2|5⁻²⁺¹=5⁻¹=1/5 (-2;1/5)
-1|5⁻¹⁺¹=5⁰=1 (-1;1)
0|5⁰⁺¹=5¹=5 (0;5)
1|25 (1;25)
2|125 (2;125)
график во вложении