已知(根号x-1 2x4次方跟)n的展开式中,前三项
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![已知(根号x-1 2x4次方跟)n的展开式中,前三项](/uploads/image/f/4200190-70-0.jpg?t=%E5%B7%B2%E7%9F%A5%28%E6%A0%B9%E5%8F%B7x-1+2x4%E6%AC%A1%E6%96%B9%E8%B7%9F%29n%E7%9A%84%E5%B1%95%E5%BC%80%E5%BC%8F%E4%B8%AD%2C%E5%89%8D%E4%B8%89%E9%A1%B9)
x=(4-√7)/3x²=(16+7-8√7)/9=(32-8√7)/9-9/9所以x²=(8/3)x-1即x²+1=(8/3)x所以x+1/x=8/3(x+1/x)
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x的平方-13x+1=0x+1/x=13(0)(0)两边平方x^2+2+1/x^2=169x^2+1/x^2=167(1)(1)两边再平方x^4+2+1/x^4=27889则x^4+1/x^4=278
4x^2+(6x^3-12x^4)/(3x^2)=4x^2+3x^2(2x-4x^2)/(3x^2)=4x^2+2x-4x^2=2x
x²+5x+1=0x+5+1/x=0∴x+1/x=-5x²+1/x²=(x+1/x)²-2=25-2=23(x²+1/x²)²=x
x²-3x+1=0两边同除以x得x-3+1/x=0即x+1/x=3x平方/x4次方+x平方+1这里分母是x4次方,则x平方/x4次方+x平方+1=1/x²+x²+1=﹙x
分析:降次x^2=5x-1所以(x^4+1)/x^2=[(5x-1)^2+1]/(5x-1)=(25x^2-10x+2)/(5x-1)=[25(5x-1)-10x+2]/(5x-1)=(115x-23
x²-3x+1=0同除以xx+1/x-3=0x+1/x=3两边平方x²+1/x²+2=9x²+1/x²=7x²/(x^4+3x²+
令x/1+x2次方=t分母配方得:1+x2次方+x4次方=(x2+1)^2-x^2分子分母同除x^2,得:x2次方/1+x2次方+x4次方=1/{(x2+1)^2/x^2-x^2/x^2}=1/{(1
1+x+x²+x³+……+x的2009次方=(1+x+x²+x³+x的4次方)+……+(x的2005次方+x的2006次方+x的2007次方+x的2008次方+
再问:为啥上面得4呢?再答:这个是分母的值啊~~~~再问:呃谢谢了
1/6 详解见图片.
x²-3x+1=0可以得出x≠0两边同除以x得x-3+1/x=0即x+1/x=3x²+1/x²=(x+1/x)²-2=7x⁴+1/x⁴=
x⁴+2x³+4x²+3x+2=x⁴+x³+x²+x³+x²+x+2x²+2x+2=x²(x
x²-x-1=0x²=x+1x^4=(x+1)²=x²+2x+1=(x+1)+2x+1=3x+2x^5=x^4*x=(3x+2)*x=3x²+2x=3
由X²-X-1=0,两边同时除以X,得X-1-X/1=0,则X-X/1=1两边平方得X²+1/X²=1上面的式子再两边平方,就得到x的4次方+x4次方分之一的值是1啦~
x^2+4x-1=0求2x^4-4x^2-8x+1=2x^4-4x^2-8x+1=2x^2(x^2+4x-1)-8x^3+2x^2-4x^2-8x+1=-8x^3+2x^2-4x^2-8x+1=-8x
x平方-3x+1=0二边同除以xx-3+1/x=0x+1/x=3x^2+1/x^2=(x+1/x)^2-2=3^2-2=7x^4+1/x^4=(x^2+1/x^2)^2-2=7^2-2=47