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第1点直线方程及位置关系(★★★)必做1动点M(x,y)满足(x-sinα)2+(y-cosα)21/2=|xsinα+ycosα-1|(其中α为常数),那么动点M的轨迹是()A.直线B.圆C.双曲线D.抛物线牛刀小试精妙解法动点M(x,y)的几何意义是到定点P(sinα,cosα)的距离等于到定直线l:xsinα+ycosα-1=0的距离,又P∈l,所以点M的轨迹是过P且垂直于l的直线.故选A.(★★★★)必做2数学家欧拉在1765年提出定理:三角形的外心、
The 1st point linear equation and positional relationship (★★★) must be a moving point M(x,y) to satisfy (x-sinα)2+(y-cosα)21/2=|xsinα+ycosα-1| ( α is a constant), then the trajectory of the moving point M is () A. The straight line B. The circle C. The hyperbola D. The parabolic chopper small test The fine solution The moving point M(x,y) is the geometric meaning of the fixed point P(sinα,cosα) The distance is equal to the distance from the fixed line l:xsinα+ycosα-1=0, and P∈l, so the trajectory of point M is a straight line passing P and perpendicular to l. Therefore, A. (★★★★) must be selected. 2 The mathematician Euler put forward the theorem in 1765: the triangle’s heart,