(1-2/1)3/1-1)(1-4/1)(5/1-1)…(2009/1-1)(1-2010/1)等于几?
郝广峰回答:
(1-2/1)(3/1-1)(1-4/1)(5/1-1)…(2009/1-1)(1-2010/1)
=1/2×(-2/3)×3/4×(-4/5)×……×(-2008/2009)×2009/2010
总共有2010-1=2009个数,则负数的个数为(2009-1)÷2=1004个,所以积是正数
=1/2010
(1-2/1)3/1-1)(1-4/1)(5/1-1)…(2009/1-1)(1-2010/1)等于几?
郝广峰回答:
(1-2/1)(3/1-1)(1-4/1)(5/1-1)…(2009/1-1)(1-2010/1)
=1/2×(-2/3)×3/4×(-4/5)×……×(-2008/2009)×2009/2010
总共有2010-1=2009个数,则负数的个数为(2009-1)÷2=1004个,所以积是正数
=1/2010