急求一道小学六年级速算奥数题!求解:1/2/(1+1/2)+1/3/(1+1/2)*(1+1/3)+1/4/(1+1/2)*(1+1/3)*(1+1/4)+...+1/2005/(1+1/2)*(1+1/3)*(1+1/4)...*(1+1/2005)各位大侠帮忙解一下 谢谢!
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急求一道小学六年级速算奥数题!求解:1/2/(1+1/2)+1/3/(1+1/2)*(1+1/3)+1/4/(1+1/2)*(1+1/3)*(1+1/4)+...+1/2005/(1+1/2)*(1+1/3)*(1+1/4)...*(1+1/2005)各位大侠帮忙解一下 谢谢!
急求一道小学六年级速算奥数题!
求解:1/2/(1+1/2)+1/3/(1+1/2)*(1+1/3)+1/4/(1+1/2)*(1+1/3)*(1+1/4)+...+1/2005/(1+1/2)*(1+1/3)*(1+1/4)...*(1+1/2005)
各位大侠帮忙解一下 谢谢!
急求一道小学六年级速算奥数题!求解:1/2/(1+1/2)+1/3/(1+1/2)*(1+1/3)+1/4/(1+1/2)*(1+1/3)*(1+1/4)+...+1/2005/(1+1/2)*(1+1/3)*(1+1/4)...*(1+1/2005)各位大侠帮忙解一下 谢谢!
原式=1/2/(3/2)+1/3/(3/2)*(4/3)+1/4/(3/2)*(4/3)*(5/4)+...+1/2005/(3/2)*(4/3)*(5/4)...*(2006/2005)
=1/2/(3/2)+1/3/(4/2)+1/4/(5/2)+...+1/2005/(2006/2)
=1/2*2/3+1/3*2/4+1/4*2/5+...+1/2005*2/2006
=2(1/2*1/3+1/3*1/4+1/4/*1/5+...+1/2005*1/2006)
=2(1/2-1/3+1/3-1/4+1/4-1/5+...+1/2005-1/2006)
=2(1/2-1/2006)
=1-1/1003
=1002/1003
(1/n)/[(1+1/2)(1+1/3)…(1+1/n)]=(1/n)/[(3/2)*(4/3)*…*(n+1)/n]=(1/n)/[(n+1)/2]=2/[n(n+1)]=2[1/n-1/(n+1)]
所以原式=2*(1/2-1/3+1/3-1/4+1/4-1/5................+1/2005-1/2006)=2(1/2-1/2006)=1002/1003
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