Question

数学题目,高手进,必须有过程!方括号代表根号

Answer 1

(1).1/a(a-1)=1/(a-1)-1/a=A/a-B/(a-1)

故A=-1,B=-1

(2).另一边长为(10a+b)/2-(4a+3b)=a-2.5b

故面积为(4a+3b)*(a-2.5b)=4a^2-7ab-7.5b^2

(3).1/(a+b)+1/b+b/a(a+b)

=(a+b)/a(a+b)+1/b

=1/a+1/b

=(a+b)/ab

代入得（2根号5）/（5-1/4）=(8根号5)/9