1.試求下列各級數和: 1/(4k2-1) =? 1/ ( + ) = ?
2.試求1 / 1*2 + 1 / 1*2+2*3 + 1 / 1*2+2*3+3*4 +……+ n / 1*2+2*3+…+n(n+1)=?
3.試求 lx 1! + 2x2! + 3x3! + ... + 20x20! =?