..若4x/(x²-4)=a/(x+2)-b/(x-2),求|a+b|.
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..若4x/(x²-4)=a/(x+2)-b/(x-2),求|a+b|.
..若4x/(x²-4)=a/(x+2)-b/(x-2),求|a+b|.
..若4x/(x²-4)=a/(x+2)-b/(x-2),求|a+b|.
两边同乘以x^4-4即(x+2)(x-2),则
4x=a(x-2)-b(x+2)=(a-b)x-2(a+b)
由于上式对任意x都成立,所以x对应项的系数相等
即-2(a+b)=0
从而|a+b|=a+b=0