已知实数x,y满足(x-y+6)(x+y-6)≥0,1≤x≤4,(1)求x^2+y^(2)-2的取值范围,(2)求y/(x-3)的取值范围.

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已知实数x,y满足(x-y+6)(x+y-6)≥0,1≤x≤4,(1)求x^2+y^(2)-2的取值范围,(2)求y/(x-3)的取值范围.
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已知实数x,y满足(x-y+6)(x+y-6)≥0,1≤x≤4,(1)求x^2+y^(2)-2的取值范围,(2)求y/(x-3)的取值范围.
已知实数x,y满足(x-y+6)(x+y-6)≥0,1≤x≤4,(1)求x^2+y^(2)-2的取值范围,(2)求y/(x-3)的取值范围.

已知实数x,y满足(x-y+6)(x+y-6)≥0,1≤x≤4,(1)求x^2+y^(2)-2的取值范围,(2)求y/(x-3)的取值范围.


原不等式可以化简成:
6-x≤y≤6+x
线性规划的题一定要画图,如下图:

阴影就是题设区域,易知:

点O到直线x+y-6=0的距离是:√(x²+y²)最小,此时:(x²+y²)-2有最小值,即:
(|6|/√2)²=18,因此:
(x²+y²)-2 ≥16
点O到最上面阴影部分的点(4,10)是√(x²+y²)的最大值,因此:
√(4²+10²)=√116
(x²+y²)-2 ≤114
综上:16≤(x²+y²)-2≤114
当y=6-x时,y/(x-3)有最小值:(6-x)/(x-3) = -1+[3/(x-3)],即:x=1时有最小值:-5/2
当y=6+x时,y/(x-3)有最大值:(6+x)/(x-3) =1+ [9/(x-3)],即:x=4是有最大值:10
因此:
-5/2 ≤y/(x-3)≤10