已知x+y=-4,xy=-12,求(x+1/y+1 )+ ( y+1/x+1)的值
问题描述:
已知x+y=-4,xy=-12,求(x+1/y+1 )+ ( y+1/x+1)的值
要写过程啊
答
x+y=-4,则(x+y)²=x²+2xy+y²=(-4)²=16所以x²+y²=16-2xy=16+24=40(x+1/y+1 )+ ( y+1/x+1)=(x+1)²/[(x+1)(y+1)]+(y+1)²/[(x+1)(y+1)]=[(x+1)²+(y+1)²]/[(x+1)(y...