作业帮1.计算5a/(6a^2c)-7b/(12ac^2)+11c/8a^2b2.计算[y/(x^2-xy)+x(y^2-xy)]/(xy)3.计算{(b-c)/[(a-b)(a-c)]}+{(a-c)/[(b-a)(b-c)]}+{(a-b)/[(c-a)(c-b)]}4.已知3x/(x^2-1)=A/(x+1)+B/(x-1),求A、B的值.
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![1.计算5a/(6a^2c)-7b/(12ac^2)+11c/8a^2b2.计算[y/(x^2-xy)+x(y^2-xy)]/(xy)3.计算{(b-c)/[(a-b)(a-c)]}+{(a-c)/[(b-a)(b-c)]}+{(a-b)/[(c-a)(c-b)]}4.已知3x/(x^2-1)=A/(x+1)+B/(x-1),求A、B的值.](/uploads/image/z/1721406-30-6.jpg?t=1.%E8%AE%A1%E7%AE%975a%2F%286a%5E2c%29-7b%2F%2812ac%5E2%29%2B11c%2F8a%5E2b2.%E8%AE%A1%E7%AE%97%5By%2F%28x%5E2-xy%29%2Bx%28y%5E2-xy%29%5D%2F%28xy%293.%E8%AE%A1%E7%AE%97%7B%28b-c%29%2F%5B%28a-b%29%28a-c%29%5D%7D%2B%7B%28a-c%29%2F%5B%28b-a%29%28b-c%29%5D%7D%2B%7B%28a-b%29%2F%5B%28c-a%29%28c-b%29%5D%7D4.%E5%B7%B2%E7%9F%A53x%2F%28x%5E2-1%29%3DA%2F%28x%2B1%29%2BB%2F%28x-1%29%2C%E6%B1%82A%E3%80%81B%E7%9A%84%E5%80%BC.)
1.计算5a/(6a^2c)-7b/(12ac^2)+11c/8a^2b2.计算[y/(x^2-xy)+x(y^2-xy)]/(xy)3.计算{(b-c)/[(a-b)(a-c)]}+{(a-c)/[(b-a)(b-c)]}+{(a-b)/[(c-a)(c-b)]}4.已知3x/(x^2-1)=A/(x+1)+B/(x-1),求A、B的值.
1.计算5a/(6a^2c)-7b/(12ac^2)+11c/8a^2b
2.计算[y/(x^2-xy)+x(y^2-xy)]/(xy)
3.计算{(b-c)/[(a-b)(a-c)]}+{(a-c)/[(b-a)(b-c)]}+{(a-b)/[(c-a)(c-b)]}
4.已知3x/(x^2-1)=A/(x+1)+B/(x-1),求A、B的值.
1.计算5a/(6a^2c)-7b/(12ac^2)+11c/8a^2b2.计算[y/(x^2-xy)+x(y^2-xy)]/(xy)3.计算{(b-c)/[(a-b)(a-c)]}+{(a-c)/[(b-a)(b-c)]}+{(a-b)/[(c-a)(c-b)]}4.已知3x/(x^2-1)=A/(x+1)+B/(x-1),求A、B的值.
(1) 5a/(6a^2c)-7b/(12ac^2)+11c/8a^2b =(20abc-14a^2b+33c^3)/(24a^2bc^2) (2) [y/(x^2-xy)+x(y^2-xy)]/(xy) =((y^2-x^2)/(xy(x-y))/(xy) =-(x+y)/(x^2y^2) (3) {(b-c)/[(a-b)(a-c)]}+{(a-c)/[(b-a)(b-c)]}+{(a-b)/[(c-a)(c-b)]} =(-(b-c)^2-(a-c)(c-a)-(a-b)^2)/((a-b)(b-c)(c-a)) =2(ab+bc-ac-b^2)/((a-b)(b-c)(c-a)) (4) 3x/(x^2-1)=A/(x+1)+B/(x-1)=(A(x-1)+B(x+1)/((x+1)(x-1)) =((A+B)x+(B-A))/*x^2-1) 上式对任何x成立 所以:A+B=3 B-A=0 所以:A=3/2,B=3/2