数学!高手!
1+1/1×2+1/2×3+……1/8×9=?
简便方法,告诉我怎样解
参考答案:1+1/1×2+1/2×3+……1/8×9
=1+(1-1/2)+(1/2-1/3)+(1/3-1/4)+......+(1/8-1/9)
=1+1-1/2+1/2-1/3+1/3-1/4+......+1/8-1/9
=1+1-1/9
=2-1/9
=1又8/9
1+1/1×2+1/2×3+……1/8×9=?
简便方法,告诉我怎样解
参考答案:1+1/1×2+1/2×3+……1/8×9
=1+(1-1/2)+(1/2-1/3)+(1/3-1/4)+......+(1/8-1/9)
=1+1-1/2+1/2-1/3+1/3-1/4+......+1/8-1/9
=1+1-1/9
=2-1/9
=1又8/9