已知P(x,y)是圆C:x^2+(y-4)^2=1外一点,过P作圆C的切线,切点为A,B,记:四边形PACB面积为f(P)求:(2)当P(x,y)在直线3x+4y-6=0上运动时,求f(P)的最小值(3)当P在圆(x+4)^2+(y-1)^2=4上运动时,指
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已知P(x,y)是圆C:x^2+(y-4)^2=1外一点,过P作圆C的切线,切点为A,B,记:四边形PACB面积为f(P)求:(2)当P(x,y)在直线3x+4y-6=0上运动时,求f(P)的最小值(3)当P在圆(x+4)^2+(y-1)^2=4上运动时,指
已知P(x,y)是圆C:x^2+(y-4)^2=1外一点,过P作圆C的切线,切点为A,B,记:四边形PACB面积为f(P)
求:(2)当P(x,y)在直线3x+4y-6=0上运动时,求f(P)的最小值
(3)当P在圆(x+4)^2+(y-1)^2=4上运动时,指出f(P)的取值范围
(4)当P在椭圆(x^2)/4+y^2=1上运动时f(P)=5是否成立?若能,求出P点坐标,若不能,说明理由.
已知P(x,y)是圆C:x^2+(y-4)^2=1外一点,过P作圆C的切线,切点为A,B,记:四边形PACB面积为f(P)求:(2)当P(x,y)在直线3x+4y-6=0上运动时,求f(P)的最小值(3)当P在圆(x+4)^2+(y-1)^2=4上运动时,指
(1)四边形PACB面积为f(P)是三角形PAC的2倍,点P到切点的距离=√[x²+(y-4)²-1],f(P)=2√[x²+(y-4)²-1]/2=√[x²+(y-4)²-1];
(2)当P(x,y)在直线3x+4y-6=0上,x=(6-4y)/3,则f(P)=√[(6-4y)²/9+(y-4)²-1]=√[25(y-12/5)²+27]/3,当y=12/5时f(P)有最小值√3;
(3)当P在圆(x+4)²+(y-1)²=4上运动时,f(P)大小与动点P与圆C:x²+(y-4)²=1的距离成正比,动P点与圆C的最近最远点在两圆心连线上,直线方程为:y=3x/4+4,与圆(x+4)²+(y-1)²=4的交点(-12/5,11/5),(-28/5,-1/5),f(P)=√[x²+(y-4)²-1]=2√2,f(P)=4√3,f(P)的取值范围[2√2,4√3];
(4)当P在椭圆x²/4+y²=1上,x²=4-4y²代入f(P)=√[x²+(y-4)²-1]=√[73/3-3(y+4/3)²],当y=-4/3时,有最大值√219/3,√219/3<5,f(P)=5不成立.