общий корень 3 делим на 4
<span>4к и 2с = 36000р. </span>
<span>2к и 3с = 22000р. </span>
<span>Методом подбора можно решить... </span>
<span>кресло=8000р </span>
<span>стол=2000р</span>
Sinx +Sin5x - Sin3x - Sin7x = 0
(Sinx -Sin7x) + ( Sin5x -Sin3x) = 0
-2Sin3x Cos4x + 2Sin2xCos4x = 0
Cos4x(-2Sin3x + 2Sin2x) = 0
Cos4x = 0 или -2Sin3x +2Sin2x = 0
4x = π/2 + πk , k ∈Z Sin3x -Sin2x = 0
x = π/8 + πk/4 , k ∈Z 2Sin0,5x Cos2,5x = 0
Sin0,5x = 0 или Сos2,5x = 0
0,5x = πn, n ∈Z 2,5x = π/2 +πm, x = 2πn, n∈Z x = π/5 + πm, m∈Z