Вложение .......................................
X^2 - 3X = 0
X * ( X - 3 ) = 0
X = 0
X - 3 = 0 ---> X = 3
...................................................
1) X^2 - 3X + 12K = 0
0 ^2 - 3 * 0 + 12K = 0
12K = 0
K = 0
2) X^2 - 3X + 12K = 0
3 ^2 - 3 * 3 + 12K = 0
12K = 0
K = 0
.................................................
ОТВЕТ: при К = 0
1000 - 487 = 513 рублей клиент потратил на бензин.
Следовательно:
Ответ: 18 литров.
Cos(6x) = cos^2(3x) - sin^2(3x)
sin(6x) = 2sin(3x)*cos(3x)
cos^2(3x) - sin^2(3x) - 2√3*sin(3x)*cos(3x) = -cos^2(3x) - sin^2(3x)
2cos^2(3x) - 2√3*sin(3x)*cos(3x) = 0
2cos(3x)*(cos(3x) - √3*sin(3x)) = 0
1) cos(3x) = 0, 3x = π/2 + πk, x = π/6 + πk/3
2) √3*sin(3x) = cos(3x), tg(3x) = 1/√3, 3x = π/6 + πk, x = π/18 + πk/3
Sin(3x)*cos(4x) + sin(4x)*cos(3x)≡ sin(3x+4x)≡ sin(7x)
sin(7x) = 1,
7x = (п/2) + 2п*n, n∈Z,
x = (п/14) + (2п*n/7).