x(x+2)分之1+(x+2)(x+4)分之1+(x+4)(x+6)分之1 快啊急用
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x(x+2)分之1+(x+2)(x+4)分之1+(x+4)(x+6)分之1 快啊急用
x(x+2)分之1+(x+2)(x+4)分之1+(x+4)(x+6)分之1 快啊急用
x(x+2)分之1+(x+2)(x+4)分之1+(x+4)(x+6)分之1 快啊急用
第一项,分母是(x+2)?还是x(x+2)?
第二项,分母是(x+4)?还是(x+2)(x+4)?
第三项……
应该是后者吧?
如果是的话:
解1:
1/[x(x+2)]+1/[(x+2)(x+4)]+1/[(x+4)(x+6)]
=(x+4)(x+6)/[x(x+2)(x+4)(x+6)]+x(x+6)/[x(x+2)(x+4)(x+6)]+x(x+2)/[x(x+2)(x+4)(x+6)]
=[(x+4)(x+6)+x(x+6)+x(x+2)]/[x(x+2)(x+4)(x+6)]
=(x^2+10x+24+x^2+6x+x^2+2x)/[x(x+2)(x+4)(x+6)]
=3(x^2+6x+8)/[x(x+2)(x+4)(x+6)]
=3(x+2)(x+4)/[x(x+2)(x+4)(x+6)]
=3/[x(x+6)]
解2:
1/[x(x+2)]+1/[(x+2)(x+4)]+1/[(x+4)(x+6)]
=(1/2)[1/x-1/(x+2)]+(1/2)[1/(x+2)-1/(x+4)]+(1/2)[1/(x+4)-1/(x+6)]
=(1/2)[1/x-1/(x+6)]
=(1/2)[(x+6)-x]/[x(x+6)]
=3/[x(x+6)]
x(x+2)分之1+(x+2)(x+4)分之1+(x+4)(x+6)分之1
=1/2[1/x-1/(x+2)+1/(x+2)-1/(x+4)+1/(x+4)-1/(x+6)]
=1/2[1/x-1/(x+6)]
=1/2*6/[x(x+6)]
=3/(x²+6x)
x(x+2)分之1+(x+2)(x+4)分之1+(x+4)(x+6)分之1
=1/2[2/x(x+2)+2/(x+2)(x+4)+2/(x+4)(x+6)]
=1/2[1/x-1/(x+2)+1/(x+2)-1/(x+4)+1/(x+4)-1/(x+6)]
=1/2[1/x-1/(x+6)]
=1/2[6/x(x+6)]
=3/x(x+6)