几道分式数学题
问题描述：
几道分式数学题
1.化简[(x-1)/(x+1)-(x+1)/(x+2)]+(x+3)/(x^2+4x+4)=__________
2.a＞b＞0,a^2+b^2=4ab,则(a+b)/(a-b)的值为__________
3.若ab=2 a+b=-1 则1/a+/b的值为________
答
1.化简为(x+3)/[(x+1)(x+2)^2]
2.a+b>0 a-b>0
(a+b)^2=a^2+b^2+2ab=4ab+2ab=6ab a+b=√6ab
(a-b)^2=a^2+b^2-2ab=4ab-2ab=2ab a-b=√2ab
(a+b)/(a-b)=√3
3.1/a+/b=(a+b)/ab=-1/2