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