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问题: 化简:1+sin8a-cos8a/1+sin8a+cos8a等于

解答:

 (1+sin8a-cos8a)/(1+sin8a+cos8a)
= (1-cos8a+sin8a)/(1+cos8a+sin8a)
= (2sin²4a+2sin4acos4a)/(2cos²4a+2sin4acos4a)
= [2sin4a(sin4a+cos4a)]/[2cos4a(cos4a+sin4a)]
= tan4a