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已知函数f(x)=x2-4,设曲线y=f(x)在点(xn,f(xn))处的切线与x轴的交点...
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已知函数f(x)=x
2-4,设曲线y=f(x)在点(x
n,f(x
n))处的切线与x轴的交点为(x
n+1,0)(n∈N*),其中x
1为正实数.
(Ⅰ)用x
n表示x
n+1;
(Ⅱ)若x
1=4,记
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEoAAAAxCAYAAAB9NT9zAAAAAXNSR0IArs4c6QAAAARnQU1BAACx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)
,证明数列{a
n}成等比数列,并求数列{x
n}的通项公式;
(Ⅲ)若x
1=4,b
n=x
n-2,T
n是数列{b
n}的前n项和,证明T
n<3.
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