若a 乘x-1的绝对值=-b乘(xy-2)的平方,且ab>0,求1/xy+1/(x+!)(y+1)+.+1/(x+2007)(y+2007)的值
问题描述：
若a 乘x-1的绝对值=-b乘(xy-2)的平方,且ab>0,求1/xy+1/(x+!)(y+1)+.+1/(x+2007)(y+2007)的值
答
a|x-1|=-b(xy-2)^2 a|x-1|+b(xy-2)^2=0 ab>0 若a=0 所以a|x-1|0 则a|x-1|>=0,b(xy-2)^2>=0 相加等于0 所以a|x-1|=0,b(xy-2)^2=0 a和b不等于0 所以x-1=0,xy-2=0 x=1,y=2 1/xy+1/(x+1)(y+1)+……+1/(x+2007)(y+2007) =...