b^3+3b^2+3b+1=(b+1)^3
1/b+1=(b+1)/b
(b+1)^3/b : (b+1)/b = (b+1)^2 = b^2+2b+1
<span>cos х - 0.5=0</span>
<span><span>cos х = 0.5</span></span>
x=+-pi/3+2pin, n є Z
s² - 3s + 2 < 0
+ - +
_________₀_____________₀__________
1 2
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Ответ : 1 < s < 2