1+cos^2(2x+3y-1)=(x^2+y^2+2(x+1)(1-y))/(x-y+1) 求实数xy最小值写明方法

1+cos^2(2x+3y-1)=(x^2+y^2+2(x+1)(1-y))/(x-y+1) 求实数xy最小值
写明方法

1+cos^2(2x+3y-1)=(x^2+y^2+2(x+1)(1-y))/(x-y+1)
1+cos^2(2x+3y-1)=(x^2+y^2+2x+2-2xy-2y)/(x-y+1)
1+cos^2(2x+3y-1)=((x-y)^2+2(x-y)+2)/(x-y+1)=((x-y+1)^2+1)/x-y+1
1+cos^2(2x+3y-1)=(x-y+1)+1)/(x-y+1)
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