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