1.1/1*2+1/2*3+1/3*4+……+1/

1.1/1*2+1/2*3+1/3*4+……+1/n(n+1) 2.1/1*3+1/3*5+1/5*7+……+1/(2n

1个回答

1/1*3+1/3*5+1/5*7+.+1/（2n-1）(2n+1)=n/(2n+1)
探究1/1*2+1/2*3+1/3*4+...+1/n(n+1)= 若1/1*3+1/3*5+1/5*7+.1/(2n-
1/(√3 +1) +( 1/√5+√3 )+ (1/√7+√5)+.+{1/√(2n+1)+√(2n-1)}
1/(1*2*3)+1/(2*3*4)+1/(3*4*5)+.+1/[n(n+)(n+)]
1*2+2*3+3*4+4*5+5*6+6*7+…+n(n+1)=n(n+1)(n+2)/3
1/1*5+1/3*7+1/5*9+.+1/(2n-1)(2n+3)
求和1/1·3+1/3·5+1/5·7+...+1/(2n+1)(2n-1)
求和:1/(1*3)+1/(3*5)+1/(5*7)+...+1/(2n-1)(2n+1)=?
已知1*1+2*2+3*3+……+n*n=1/6n(n+1)(2n+1),求1*2+3*4+5*6+7*8+.+49*5
1/2-1/n+1＜1/2^2+1/3^2+……+1/n^2＜n-1/n(n=2,3,4,5,6.