Sina-2sin3a-sin5a _____________ cosa-2sin3a-cos5a

Question

Sina-2sin3a-sin5a
_____________
cosa-2sin3a-cos5a

Comments

точно ?

Answer 1

Sina - 2sin3a-sin5a
_______________
cosa-2sin3a-cos5a
* * * * * *
лучше так 
(2cos3α - (sin5α - sinα) ) / (-2sin3α - (cos5α - cosα) ) =
(2cos3α - 2sin2α*cos3α) / (-2sin3α+2sin3α *sin2α)   =
2cos3α(1 -sin2α) / -2sin3α(1-sin2α)  =   - ctq3α.