好简单,呵呵~!~!~!我是深圳大学数学学院的学生,,,原式=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6) 括号拆开后你就知道很多项是可以抵消的,其实就等于1-1/6=5/6 等到你以后学你就知道了,真正变态的数学是怎么样的~!
1*1/2+1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1-1/6
=5/6
=1+1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=5/6
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1-1/6
=5/6