(x-y)分之一-(x+y)分之一+(x²-y²)分之一(计算)还有2(x-3)-(x-1)²-(x+3)(x-3)=0这道题
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(x-y)分之一-(x+y)分之一+(x²-y²)分之一(计算)还有2(x-3)-(x-1)²-(x+3)(x-3)=0这道题
(x-y)分之一-(x+y)分之一+(x²-y²)分之一(计算)
还有2(x-3)-(x-1)²-(x+3)(x-3)=0这道题
(x-y)分之一-(x+y)分之一+(x²-y²)分之一(计算)还有2(x-3)-(x-1)²-(x+3)(x-3)=0这道题
1/(x-y)-1/(x+y)+1/(x²-y²)
=(x+y-x+y+1)/(x-y)(x+y)
=(2y+1)/(x²-y²)
1/(x-y)-1/(x+y)+1/(x²-y²)
=(x+y-x+y+1)/(x-y)(x+y)
=(2y+1)/(x²-y²)
2(x-3)-(x-1)²-(x+3)(x-3)=0
同时乘以-1得 (x-1)² -2(x-3)+(x-3)(x+3)=0
提供因式: (x...
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1/(x-y)-1/(x+y)+1/(x²-y²)
=(x+y-x+y+1)/(x-y)(x+y)
=(2y+1)/(x²-y²)
2(x-3)-(x-1)²-(x+3)(x-3)=0
同时乘以-1得 (x-1)² -2(x-3)+(x-3)(x+3)=0
提供因式: (x-1)² +(x-3)【(x+3)-2】=0
(x-1)² +(x-3)(x+1)=0
展开 x^2-2x+1+x^2-2x-3=0
2x^2-4x-2=0
同时除以2得 x^2-2x-1=0
用公式法求解 x=1±√2
希望你明白
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1/(x-y)-1/(x+y)+1/(x²-y²)
=x+y/(x²-y²)-(x-y)/(x²-y²)+1/(x²-y²)
=(x+y-x+y+1)/(x²-y²)
=(2y+1)/(x²-y²)
2(x-3)-(x-1)²-(x+3)...
全部展开
1/(x-y)-1/(x+y)+1/(x²-y²)
=x+y/(x²-y²)-(x-y)/(x²-y²)+1/(x²-y²)
=(x+y-x+y+1)/(x²-y²)
=(2y+1)/(x²-y²)
2(x-3)-(x-1)²-(x+3)(x-3)=0
(x-3) (2(x-1)²)-(x+3))=0
得 (x-3) =0 或 2(x-1)²)-(x+3)=0
检验 x=3不符要求
所以2(x-1)²-(x+3)=0
解得 x=1±√2
收起
1/(x-y)-1/(x+y)+1/(x²-y²)
=(x+y-x+y+1)/(x-y)(x+y)
=(2y+1)/(x²-y²)