令a = arccos33/65
则有,
cos a = 33/65,sin a = 56/65
令b = arctan4/3
则有,
tan b = 4/3,sin b = 4/5 ,cos b = 3/5
sin(arccos33/65+arctan4/3)
= sin(a+b)
= sin a cos b + cos a sin b
= (56/65)(3/5) + (33/65)(4/5)
= 300/325
= 12/13
令a = arccos33/65
则有,
cos a = 33/65,sin a = 56/65
令b = arctan4/3
则有,
tan b = 4/3,sin b = 4/5 ,cos b = 3/5
sin(arccos33/65+arctan4/3)
= sin(a+b)
= sin a cos b + cos a sin b
= (56/65)(3/5) + (33/65)(4/5)
= 300/325
= 12/13