x(1/2*4+1/4*6+1/6*8+……+1/2n*(2n+2))=2006/2008
问题描述:
x(1/2*4+1/4*6+1/6*8+……+1/2n*(2n+2))=2006/2008
x的值是多少?
答
x/2(1/1*2+1/2*3+1/3*4+……+1/n*(n+1))=2006/2008
x/2(1-1/2+1/2-1/3+1/3-1/4+1/4……-1/n+1/n-1/(n+1))=2006/2008
x/2 * n/(n+1)=1003/1004
x=2*(1003/1004)*(n+1)/n