已知點(diǎn)P(5,-3),點(diǎn)Q在圓x2+y2=4上運(yùn)動(dòng),線段PQ的中點(diǎn)為M,求點(diǎn)M的軌跡方程.
已知點(diǎn)P(5,-3),點(diǎn)Q在圓x2+y2=4上運(yùn)動(dòng),線段PQ的中點(diǎn)為M,求點(diǎn)M的軌跡方程.
優(yōu)質(zhì)解答
設(shè)M(x,y),Q(a,b)
由P(5,-3),M是PQ的中點(diǎn)
故有a=2x-5,b=2y+3
又Q為圓x
2+y
2=4上一動(dòng)點(diǎn),
∴(2x-5)
2+(2y+3)
2=4,
整理得(x-
)
2+(y+
)
2=1,
故PQ的中點(diǎn)M的軌跡方程是(x-
)
2+(y+
)
2=1.
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