2000x^3=2001y^3=2002z^3xyz>0______________________ ______ _____ ____3/ =3/ 3/ 3/\/ 2000x^2+2001y^2+2002z^2 \/ 2000 + \/ 2001 \/ 2002求 1/x+1/y+1/z 的值Note:此为三次根号______3/\/

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2000x^3=2001y^3=2002z^3xyz>0______________________ ______ _____ ____3/ =3/ 3/ 3/\/ 2000x^2+2001y^2+2002z^2 \/ 2000 + \/ 2001 \/ 2002求 1/x+1/y+1/z 的值Note:此为三次根号______3/\/
2000x^3=2001y^3=2002z^3
xyz>0
______________________ ______ _____ ____
3/ =3/ 3/ 3/
\/ 2000x^2+2001y^2+2002z^2 \/ 2000 + \/ 2001 \/ 2002
求 1/x+1/y+1/z 的值
Note:此为三次根号
______
3/
\/

2000x^3=2001y^3=2002z^3xyz>0______________________ ______ _____ ____3/ =3/ 3/ 3/\/ 2000x^2+2001y^2+2002z^2 \/ 2000 + \/ 2001 \/ 2002求 1/x+1/y+1/z 的值Note:此为三次根号______3/\/
令2000x^3=2001y^3=2002z^3=N,题中方程立方得
2000x^2+2001y^2+2000z^2=(3次√2000+3次√2001+3次√2002)^3
两边同除以N
左边:(2000x^2+2001y^2+2000z^2)/N=2000x^2/N+2001y^2/N+2000z^2/N
=2000x^2/2000x^3+2001y^2/2001y^3+2000z^2/2002z^3
=1/x+1/y+1/z
右边:(3次√2000+3次√2001+3次√2002)^3/N
=[(3次√2000/3次√N)+(3次√2001/3次√N)+(3次√2002/3次√N)]^3
=[(3次√2000/3次√2000x^3)+(3次√2001/3次√2001y^3)+(3次√2002/3次√2002z^3)]
=(1/x+1/y+1/z)^3
即是 1/x+1/y+1/z=(1/x+1/y+1/z)^3
化简 (1/x+1/y+1/z)^2=1
因为 2000x^3=2001y^3=2002z^3且xyz大于0
所以 x>0,y>0,z>0
所以 1/x+1/y+1/z=1

左边:(2000x^2+2001y^2+2000z^2)/N=2000x^2/N+2001y^2/N+2000z^2/N
=2000x^2/2000x^3+2001y^2/2001y^3+2000z^2/2002z^3
=1/x+1/y+1/z
右边:(3次√2000+3次√2001+3次√2002)^3/N
=[(3次√2000/3次√N)+(3次√2001...

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左边:(2000x^2+2001y^2+2000z^2)/N=2000x^2/N+2001y^2/N+2000z^2/N
=2000x^2/2000x^3+2001y^2/2001y^3+2000z^2/2002z^3
=1/x+1/y+1/z
右边:(3次√2000+3次√2001+3次√2002)^3/N
=[(3次√2000/3次√N)+(3次√2001/3次√N)+(3次√2002/3次√N)]^3
=[(3次√2000/3次√2000x^3)+(3次√2001/3次√2001y^3)+(3次√2002/3次√2002z^3)]
=(1/x+1/y+1/z)^3
即是 1/x+1/y+1/z=(1/x+1/y+1/z)^3
化简 (1/x+1/y+1/z)^2=1
因为 2000x^3=2001y^3=2002z^3且xyz大于0
所以 x>0,y>0,z>0
所以 1/x+1/y+1/z=1

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(2000x^2+2001y^2+2000z^2)/N=2000x^2/N+2001y^2/N+2000z^2/N
=2000x^2/2000x^3+2001y^2/2001y^3+2000z^2/2002z^3
=1/x+1/y+1/z
(3次√2000+3次√2001+3次√2002)^3/N
=[(3次√2000/3次√N)+(3次√2001/3次√N)...

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(2000x^2+2001y^2+2000z^2)/N=2000x^2/N+2001y^2/N+2000z^2/N
=2000x^2/2000x^3+2001y^2/2001y^3+2000z^2/2002z^3
=1/x+1/y+1/z
(3次√2000+3次√2001+3次√2002)^3/N
=[(3次√2000/3次√N)+(3次√2001/3次√N)+(3次√2002/3次√N)]^3
=[(3次√2000/3次√2000x^3)+(3次√2001/3次√2001y^3)+(3次√2002/3次√2002z^3)]
=(1/x+1/y+1/z)^3
1/x+1/y+1/z=(1/x+1/y+1/z)^3
(1/x+1/y+1/z)^2=1
因为 2000x^3=2001y^3=2002z^3且xyz大于0
所以 x>0,y>0,z>0
所以 1/x+1/y+1/z=1

收起