设f(x+y,xy)=x²+y²,则f(x,y)=(?).
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![设f(x+y,xy)=x²+y²,则f(x,y)=(?).](/uploads/image/z/4032652-4-2.jpg?t=%E8%AE%BEf%28x%2By%2Cxy%29%3Dx%26%23178%3B%2By%26%23178%3B%2C%E5%88%99f%28x%2Cy%29%3D%28%3F%29.)
设f(x+y,xy)=x²+y²,则f(x,y)=(?).
设f(x+y,xy)=x²+y²,则f(x,y)=(?).
设f(x+y,xy)=x²+y²,则f(x,y)=(?).
设x+y=a,xy=b,
则f(a,b)=x^2+b^2=(x+y)^2-2xy=a^2-2b
所以f(x,y)=x^2-2y
f(x加y,xy)=(x加y)^2-2xy.
利用整体代换思想→f(x,y)=x^2-2y.
f(x,y)是什么东西?