Question

反三角函数注意事项sin(arccos33/65+arctan4/3)=12/13把arccos33/65设为a如何求出

Answer 1

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