计算:x+(x+y)+(x+2y)+···+(x+99y)等于?

计算:x+(x+y)+(x+2y)+···+(x+99y)等于?
计算:x+(x+y)+(x+2y)+···+(x+99y)等于?

计算:x+(x+y)+(x+2y)+···+(x+99y)等于?
x+(x+y)+(x+2y)+···+(x+99y)
= (x+x+x+...(共100个x)) + (y+2y+3y+...+99y)
= 100x + (1+99)/2*99y
= 100x + 4950y

100x+4950y

x+(x+y)+(x+2y)+···+(x+99y)
=100x+y+2y+99y
=100x+00(99+1)/2y
=100x+4950y

x+(x+y)+(x+2y)+···+(x+99y)
=x×100+（y+2y+……+99y）
=100x+（1+99）×99/2×y
=100x+4950y请问 y+2y+3y 。。。到99Y 是怎么算的 ？？y+2y+……+99y=（1+2+3……+99）y (1+99)+(2+98)+(3+97)+……+（49+51...

全部展开

x+(x+y)+(x+2y)+···+(x+99y)
=x×100+（y+2y+……+99y）
=100x+（1+99）×99/2×y
=100x+4950y

收起

x+(x+y)+(x+2y)+···+(x+99y)
=100x+(y+2y+3y+...+99y)
=100x+(1+99)*99y/2
=100x+4950y