求和:1/1x4+1/4x7+···+1/(3n-2)x(3n+1)
求和:1/1x4+1/4x7+···+1/(3n-2)x(3n+1)
lim[1/(1x4)+1/(4x7)+1/(7x10)+...+1/(3n-2)x(3n+1)]=_____
1x4分之一加4x7分之一加到(3n-2)x(3n+1)分之一等于多少
数列的前N项求和数列:1/(1X3),1/(3X5),1/(5X7),……,1/[(2n-1)(2n+1)]呃,这种类型
是否存在常数C,使得等式1x4+2x7+3x10+.+n(3n+1)=n(n+c)(n+2c+1)对任意正整数n恒成立?
C语言编程s(x)=x-x3/3!+x5/5!-x7/7!+……+(-1)n-1·x2n-1/(2n-1)!
100x( 3/1x4 + 3/4x7 +3/7x10 +.3/97x100)=?注:1x4、4x7、7x10等均为分母
第三题由X(n+2)=X(n+1)-XnX3=X2-X1=3-1=2X4=-1X5=-3X6=-2X7=1X8=3X9=
数列求和 用分组求和及并项法求和 Sn=1^2-2^2+3^2-4^2+…+(-1)^(n-1)·n^2
级数1/(n^2·(n+1)^2)求和
1/2!+2/3!+3/4!+.+n/(n+1)!求和
求和(1+2)+(3+4)+...+(2n-1+2^n)