1. 正弦、余弦互化：
– sin(a + b) = sin a cos b + cos a sin b
– cos(a – b) = cos a cos b – sin a sin b
– sin(a – b) = sin a cos b + cos a sin b
– cos(a + b) = cos a cos b – sin a sin b
– cos(a – b) = cos a cos b + sin a sin b
2. 正弦、余弦互化逆运算：
– sin(a + b) = sin a cos b – cos a sin b
– cos(a – b) = cos a cos b + sin a sin b
– sin(a – b) = sin a cos b – cos a sin b
– cos(a + b) = cos a cos b + sin a sin b
– cos(a – b) = cos a cos b – sin a sin b
3. 正切、余切互化：
– tan(a + b) = tan a tan b / (1 – cos(a + b))
– tan(a – b) = tan a tan b / (1 + cos(a – b))
– tan(a – b) = tan a tan b / (1 – cos(a – b))
– tan(a + b) = tan a tan b / (1 + cos(a + b))
– tan(a – b) = tan a tan b / (1 – cos(a – b))
4. 正切、余切互化逆运算：
– tan(a + b) = tan a tan b / (1 + cos(a + b))
– tan(a – b) = tan a tan b / (1 – cos(a – b))
– tan(a – b) = tan a tan b / (1 – cos(a – b))
– tan(a + b) = tan a tan b / (1 + cos(a + b))
– tan(a – b) = tan a tan b / (1 + cos(a – b))
这些口诀可以帮助我们在进行三角函数的转换时更加快速和准确。通过不断练习和应用这些口诀，你将能够熟练掌握三角函数的转换，并在实际问题中灵活运用。
