Maths question

It is given that 1/m=1/a+b and 1/n=a+1/b
A. Express m-n in terms of a and b.
1/m=1/a+b
1/m= (1+ab)/a
m=a/(1+ab)
1/n=a+1/b
1/n= (ab+1)/b
n=b/(ab+1)
m-n
= a/(1+ab) - b/(1+ab)
= (a-b)/(1+ab)
OR
1/m=1/(a+b)
m=a+b
1/n=(a+1)/b
n=b/(a+1)
m-n
= a+b - b/(a+1)
= [a(a+1) + b(a+1) - b]/(a-1)
= (a^2 +a + ab)/(a-1)

2009-12-23 19:18:45 補充：
Just a luck ^^""

2009-12-23 19:59:27 補充：
請問樓下你是否直copy 我的- -答案＝　＝｜｜｜

i think is...

Sorry, I want to ask :

1/a+b or 1/(a+b) ?

a+1/b or (a+1)/b ?

2009-12-23 19:16:34 補充：
wow!

Very fast.