n² + x + 0.04 = n² + x + 0.2² = n² + 2*n*0.2 + 0.2² = n² + <u>0.4n</u> + 0.4 = (n+0.2)²
n² + x + 0.04 = n² + x + 0.2² = n² + 2*n*(-0.2) + 0.2² = n² - <u>0.4n</u> + 0.4 = (n-0.2)²
Ответ D
20-9x+x²=0
x²-9x+20=0
D=9² - 4*20=1
x1=(9-1)/2=4
x2=(9+1)/2=5
х=5 - больший корень
Решение
<span>Sin4xcosx-cos4xsinx>-√2/2
sin(4x - x) > - </span><span>√2/2
- arcsin( -</span>√2/2) + 2πk < 3x < π + arcsin(- √2/2) + 2πk, k ∈ Z
π/4 + 2πk < 3x < π - π/4 + 2<span>πk, k ∈ Z
</span>π/4 + 2πk < 3x < 3π/4 + 2<span>πk, k ∈ Z
</span>π/12 + 2πk/3 < 3π + 2<span>πk/3, k ∈ Z</span>