x = a^2+b^2/(a- b)and y = (a+b)/a^2- b^2
1)............fine (x+y)
2)............fine (x-y)
3)............express (x+y)/(x-y) in terms of a and b ; and
4) express (x+y)(x-y) in terms of a and b
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2008-06-19 10:47 am
回答 (2)
2008-06-19 5:39 pm
✔ 最佳答案
x = a^2+b^2/(a- b)and y = (a+b)/a^2- b^2x = a^2+b^2/(a- b)
y = (a+b)/a^2- b^2
=(a+b)/[(a+b)(a-b)
=1/a-b
x+y
= (a^2+b^2+1)/(a- b) ..(1)
x-y
= (a^2+b^2-1)/(a- b) ... (2)
(x+y)(x-y) = (1)*(2)
(a^2+b^2+1)(a^2+b^2-1) / (a-b)^2
[(a^2+b^2)^2 -1]/(a-b)
2008-06-19 5:38 pm
x= (a^2+b^2)/(a-b)
y=(a+b)/(a^2-b^2)
=(a+b)/(a+b)(a-b)
=1/(a-b)
1.(x+y)=a^2+b^2+1/(a-b)
2. (x-y)=a^2+b^2-1/(a-b)
3. x+y/x-y=a2+b2+1/a2+b2-1
4. x+y)(x-y)=(a2+b2)2-1/(a-b)2
y=(a+b)/(a^2-b^2)
=(a+b)/(a+b)(a-b)
=1/(a-b)
1.(x+y)=a^2+b^2+1/(a-b)
2. (x-y)=a^2+b^2-1/(a-b)
3. x+y/x-y=a2+b2+1/a2+b2-1
4. x+y)(x-y)=(a2+b2)2-1/(a-b)2
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