![\(4^x\leq3\cdot 2^{\sqrt{x}}\cdot 2^x+4\cdot 4^{\sqrt{x}}\) \(4^x\leq3\cdot 2^{\sqrt{x}}\cdot 2^x+4\cdot 4^{\sqrt{x}}\)](https://tex.z-dn.net/?f=%5C%284%5Ex%5Cleq3%5Ccdot%202%5E%7B%5Csqrt%7Bx%7D%7D%5Ccdot%202%5Ex%2B4%5Ccdot%204%5E%7B%5Csqrt%7Bx%7D%7D%5C%29)
Обе части неравенства разделим на 4ˣ
![\(1\leq3\cdot 2^{\sqrt{x}-x}+4\cdot 4^{\sqrt{x}-x}\) \(1\leq3\cdot 2^{\sqrt{x}-x}+4\cdot 4^{\sqrt{x}-x}\)](https://tex.z-dn.net/?f=%5C%281%5Cleq3%5Ccdot%202%5E%7B%5Csqrt%7Bx%7D-x%7D%2B4%5Ccdot%204%5E%7B%5Csqrt%7Bx%7D-x%7D%5C%29)
![\(4\cdot 4^{\sqrt{x}-x}+3\cdot 2^{\sqrt{x}-x}-1\geq 0\) \(4\cdot 4^{\sqrt{x}-x}+3\cdot 2^{\sqrt{x}-x}-1\geq 0\)](https://tex.z-dn.net/?f=%5C%284%5Ccdot%204%5E%7B%5Csqrt%7Bx%7D-x%7D%2B3%5Ccdot%202%5E%7B%5Csqrt%7Bx%7D-x%7D-1%5Cgeq%200%5C%29)
Замена:
, t > 0
4t² + 3t - 1 ≥ 0;
4t² + 3t - 1 = 0;
D = 9 + 16 = 25; √D = 5;
t₁ = (-3 + 5)/8 = 0,25; t₂ = (-3 - 5)/8 = -1 - не удовлетворяет условие t > 0
------ ++++
---------------------0------------0,25------------->
t ≥ 0,25;
Обратная замена:
![\( 2^{\sqrt{x}-x}\geq 0,25\) \( 2^{\sqrt{x}-x}\geq 0,25\)](https://tex.z-dn.net/?f=%5C%28%202%5E%7B%5Csqrt%7Bx%7D-x%7D%5Cgeq%200%2C25%5C%29)
![\( 2^{\sqrt{x}-x}\geq 2^{-2}\) \( 2^{\sqrt{x}-x}\geq 2^{-2}\)](https://tex.z-dn.net/?f=%5C%28%202%5E%7B%5Csqrt%7Bx%7D-x%7D%5Cgeq%202%5E%7B-2%7D%5C%29)
![\( \sqrt{x}-x\geq -2\) \( \sqrt{x}-x\geq -2\)](https://tex.z-dn.net/?f=%5C%28%20%5Csqrt%7Bx%7D-x%5Cgeq%20-2%5C%29)
√x - x + 2 ≥ 0;
Замена: √x = m, m ≥ 0
m - m² + 2 ≥ 0;
m² - m - 2 ≤ 0;
m² - m - 2 = 0;
m₁ = 2; m₂ = -1 - не удовлетворяет условие m ≥ 0.
------ +++++
-----------------0--------------2------------------>
0 ≤ m ≤ 2
Обратная замена:
√x ≤ 2
ОДЗ: x ≥ 0
x ≤ 4
x ∈ [0; 4]