a,b满足根号(a-1)+根号(b-3)=0,求下式的值。

2024-11-28 15:59:33
推荐回答(2个)
回答(1):

因根号非负,所以a=1,b=3
下面是数列问题1/1*3+1/2*4+1/3*5+……+1/2011*2013
=1/2[(1-1/3)+(1/3-1/5)+……+(1/2011-1/2013)]+1/2[(1/2-1/4)+(1/4-1/6)+……+(1/2010-1/2012)]
=1006/2013+1005/4024

回答(2):

∵√(a-1)≥0,√(b-3)≥0
∴a-1=0,b-3=0
a=1,b=3
1/ab+1/(a+1)(b+1)+1/(a+2)(b+2)+…+1/(a+2010)(b+2010)
=1/(1*3)+1/(2*4)+1/(3*5)+...+1/(2011*2013)
=1/2*(1-1/3+1/2-1/4+1/3-1/5+...+1/2011-1/2013)
=1/2*(1+1/2-1/2012-1/2013)
=4050156分之6071209