挑战习题
1/5单选题
难度:

1.

如图,已知抛物线的顶点坐标为M(1,4),与x轴交于A、B两点(点A在点B左侧),与y轴交于点C(0,3). 在对称轴上存在一点P,使|PC-PB|的值最大时,点P的坐标为(      ).



A

(1,5)

B

(1,6)

C

(1,4.5)

D

(1,6.5)

提示1:
PHA+5YWI5Yip55So5a+556ew5oCn5Y+v5rGCQ+eCueeahOWvueensOeCuU7vvIzov4dCTuS9nOebtOe6v++8jOS6pOWvueensOi9tOS6jlDvvIzlhYjmsYLov4dC44CBTueahOebtOe6v++8jOWGjeaKing9MeS7o+WFpeWHveaVsOino+aekOW8j+WNs+WPr+axgnnvvIzku47ogIzlj6/lvpdQ54K55Z2Q5qCHLjwvcD4=
正确答案:Qg==
PHA+6Kej77ya5aaC5Zu+77yaPGJyPjxpbWcgc3JjPSJodHRwczovL3AyLnFpbmdndW8uY29tL0cxL00wMC84MS8yQy9yQkFDRTFQWER4dVJUWkFrQUFBM2R4Vk5kODQzNjYucG5nIiBkYXRhLWNrZS1zYXZlZC1zcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwLzgxLzJDL3JCQUNFMVBYRHh1UlRaQWtBQUEzZHhWTmQ4NDM2Ni5wbmciIGhlaWdodD0iMjM1IiB3aWR0aD0iMTQ2Ij48YnI+5Yip55So5a+556ew5oCn5Y6f55CG77ya5rGC5Ye6Q+eCueeahOWvueensOeCuU7vvIgy77yMM++8ie+8jDxicj7ov4dC44CBTuS9nOebtOe6v++8jOS6pOWvueensOi9tOS6jueCuVDvvIw8YnI+6K6+55u057q/Qk7nmoTmlrnnqIvmmK95PWF4K2LvvIzpgqPkuYg8YnI+PGltZyBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwLzgxLzJDL3JCQUNFMVBYRHh2QlpBTXFBQUFDeW1qR1J2NDQwMS5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvODEvMkMvckJBQ0UxUFhEeHZCWkFNcUFBQUN5bWpHUnY0NDAxLnBuZyIgaGVpZ2h0PSI2MiIgd2lkdGg9Ijc2Ij7vvIw8YnI+6Kej5b6XeT0tM3grOe+8jDxicj7lvZN4PTHml7bvvIx5PTbvvIw8YnI+5pWFUOeCueWdkOagh+aYr++8iDHvvIw277yJLjwvcD4=