1.当x=1时,x-2x+3x-4x+……+99x-100x的值为( ) A.50 B.-50 C.100 D.-100
2个回答
1、-50
2、n*(n+2)+1=(n+1)²
相关问题
当x=-1时,求x+2x²+3x³+……+99x^99+100x^100的值
当X=-1时 求X+2X^2+3X^3+…+99^99+100X^100
3x(1x2+2x3+3x4+……+99x100)= (A)97x98x99 (B)98x99x100 (C)99x 1
1x1+0x1+2x2+1x2+3x3+2x3+4x4+3x4……99x99+98x99+100x100+99x100
数学题;设(x^2-x-1)^50=a100x^100+a99x^99+...+a0求a100+a99+a98+...+
当x= -1 时,求x+2x²+3x³+.+99x的99次方+100x的100次方
y=|x-1|+|x-2|+|x-3|+|x-4|+|x-5|+|x-6|……+|x-99|+|x-100|+50n的最
1X1+2X2+3X3+4X4+5X5.+98X98+99X99+100X100=?
算式:1.100又99\98x99.2.49又50\49x50
100X100—99X99+98X98+...+2X2—1X1