1)Невозможно(температура кипения 100<span>°С</span>)
2)Достоверное
9^x=3^2x
3^x+1=3^x*3
3^2x+3*3^x-4=0
назначаем 3^x=t
t²+3t-4=0
D=9+16=25=5^2
t=-3+5/2=1
t=-3-5/2<0
3^x=1
x=0
1) x²=64
x=8; -8
2) х²=19
х=√19
3) х²=-36
х=-√36
х=6;-6
4) 0,3х²=30
х²=100
х=10;-10
Ответ:
x = π + 2πn, n ∈ Z; -π/2 + 2πk, k ∈ Z.
Объяснение:
4cos²(x/2) + 0,5sinx + 3sin²(x/2) = 3
4cos²(x/2) + 2·0,5sin(x/2)·cos(x/2) + 3sin²(x/2) = 3sin²(x/2) + 3cos²(x/2)
cos²(x/2) + sin(x/2)cos(x/2) = 0
cos(x/2)[cos(x/2) + sin(x/2)] = 0
1) cos(x/2) = 0
x/2 = π/2 + πn, n ∈ Z
x = π + 2πn, n ∈ Z
2) cos(x/2) + sin(x/2) = 0
cos(x/2) = -sin(x/2)
tg(x/2) = -1
x/2 = -π/4 + πk, k ∈ Z
x = -π/2 + 2πk, k ∈ Z