Кулагина7 лет назад
1)
log5(2x - 3) > log5(x^2 - 2x);
{2x - 3 > x^2 - 2x;
{x^2 - 2x > 0;
{x^2 - 4x + 3 < 0;
{x(x - 2) > 0;
{(x - 1)(x - 3) < 0;
{x(x - 2) > 0;
{x ∈ (1; 3);
{x ∈ (-∞; 0) ∪ (2; ∞);
x ∈ (2; 3).
2)
log√2(х - 5) = 0;
x - 5 = 1;
x = 5 + 1;
x = 6.
3)
log^2(0,5)(x) + log0,5(x) > 2;
log^2(0,5)(x) + log0,5(x) - 2 > 0;
log0,5(x) = t;
t^2 + t - 2 > 0;
D = 1^2 + 4 * 2 = 9;
t = (-1 ± √9)/2 = (-1 ± 3)/2;
t1 = (-1 - 3)/2 = -2;
t2 = (-1 + 3)/2 = 1;
t ∈ (-∞; -2) ∪ (1; ∞);
[t < -2;
[t > 1;
[log0,5(x) < -2;
[log0,5(x) > 1;
[x > (1/2)^(-2);
[0 < x < 0,5;
[x > 4;
[0 < x < 0,5;
x ∈ (0; 0,5) ∪ (4; ∞).
Наименьшее целое решение: 5.