Соs3a*cos6a*cos12a=sin24a/8sin3a

Question

Соs3a*cos6a*cos12a=sin24a/8sin3a

Answer 1

cos3a*cos6a*cos12a=sin24a/8sin3a                        

8sin3a*cos3a*cos6a*cos12a=2sin12a*cos12a

4sin6a*cos6a=2sin12a

2sin12a=2sin12a

 

 

формула: 2sina*cosa=sin2a