过点(4,﹣3)作圆C:(x﹣3)2+(y﹣1)2=1的切线,求此切线的方程.
解:设过P点的圆的切线为y+3=k(x﹣4),即kx﹣y﹣4k﹣3=0
它与圆心(3,1)的距离等于半径,故k+41+k2
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