单雨童为什么为狂澜哭:约分1x2x3+2x4x6+... ...+100x200x300/2x3x4+4x6x8+... ...+200x300x400

来源:百度文库 编辑:查人人中国名人网 时间:2024/05/02 17:36:59

=1x2x3+(1x2x3)x2+.....(1x2x3)x100/2x3x4+(2x3x4)x2+.....+(2x3x4)x100
=(1x2x3)x100/(2x3x4)x100
=1x2x3/2x3x4
=1/4

1/4

1x2x3+2x4x6+... ...+100x200x300/2x3x4+4x6x8+... ...+200x300x400
=1x2x3+1x2x3 * 2 +......1x2x3 * 100/2x3x4+2x3x4 * 2+......+2x3x4 *100
=1x2x3(1+2+3+......+100)/2x3x4(1+2+3+...+100)
=1x2x3/2x3x4
=1/4