(本小题满分13分) 已知三点A（3，0），B（0，3），C，．（1）若，求角；（2）若，求的值．

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(本小题满分13分)
已知三点A（3，0），B（0，3），C，．
（1）若，求角；
（2）若，求的值．

答案

解：(1) ∵···························· 2分
由得········································ 4分
整理得
∴····························································································· 6分
∵      ∴·································································· 7分
(2) ∵
∴····························································· 8分
即····················································································· 9分
∴     
∴················································································· 10分
∴································· 13分

解析

略