解一元三次不等式如何解2t^3-3t^2+3t-1

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解一元三次不等式如何解2t^3-3t^2+3t-1解一元三次不等式如何解2t^3-3t^2+3t-1解一元三次不等式如何解2t^3-3t^2+3t-12t^3-3t^2+3t-1=t^3+(t-1)^

解一元三次不等式如何解2t^3-3t^2+3t-1
解一元三次不等式
如何解2t^3-3t^2+3t-1

解一元三次不等式如何解2t^3-3t^2+3t-1
2t^3-3t^2+3t-1=t^3+(t-1)^3
=(2t-1)(t^2-t*(t-1)+(t-1)^2)
=(2t-1)(t^2-t^2+t+t^2-2t+1)
=(2t-1)(t^2-t+1)
=(2t-1)((t-1/2)^2+3/4)

原不等式同解于:
(2t^3-t^2)+(-2t^2+t)+(2t-1)<0
t^2(2t-1)+t(2t-1)+(2t-1)<0
(2t-1)(t^2+t+1)<0
∵t^2+t+1=(t-1/2)^2+3/4)>0
∴ 2t-1<0
∴ t<1/2
∴ 原不等式的解集为:t<1/2