10、过P作PH⊥面BCC′B′,作PG⊥EF,连接GH,则∠PGH为面AEF与面BCC′B′所成的角,故PGsin∠PGH=PH=PA,则为定值,且,故P点轨迹是椭圆.

答案:

  • 答案
关闭