2sin^2 x - 10cos 2x = 9sin 2x +10 решите

2sin^2 x - 10cos 2x = 9sin 2x +102sin²x - 10(cos  ²x   - sin²x)  = 9*2sin xcosx +10*12sin²x - 10cos  ²x   +10 sin²x  = 9*2sin xcosx +10*(sin²x + cos²x) 2sin²x - 10cos  ²x   +10 sin²x  = 9*2sin xcosx +10sin ²x + 10cos²x2sin²x - 18sinxcosx -20cos²x = 0 sin²x - 9sinxcosx -10cos²x = 0 | : cos²x  ≠0 tg²x - 9tgx -10 = 0 по т. виета tgx = 10                                   tgx = -1 x = arctg10 +  πk , k  ∈ z           x = -π/4 +  πn , n  ∈z

x/2,5=-6,2/15

15x=-15,5

x=-31/30=- 1 1/30

a1=7, q=9 

a2=7*9=63

a3=63*9=567

a4=567*9=5103

 

a1=3, q=-8

a2=3*(-8)=-24

a3=-24*(-8)=192

a4=192*(-8)=-1536