Формула
sinα·cosβ=(sin(α+β)-sin(α-β))/2;
sin3x·cos2x=(sin(3x+2x)-sin(3x-2x))/2=(sin5x+sinx)/2
Уравнение принимает вид
(sin5x+sinx)/2=sin5x;
sin5x-sinx=0;
или
2·sin((5x-x)/2)·cos((5x+x)/2)=0;
2sin2x·cos3x=0
sin2x=0 или cos3x=0
2x=πk, k∈ Z или 3x=(π/2)+πn, n∈Z.
x=(π/2)k, k ∈ Z или x=(π/6) +(π/3)n, n ∈ Z
При k=0 х₁=0
k=1 x₂=π/2
k=2 x₃=2π/2=π
k=3 x₄=3π/2
k=4 x₅=4π/2=2π
n=0 x₆=(π/6)
n=1 x₇=(π/6)+(π/3)=π/2= x₂
n=2 x₈=(π/6)+(2π/3)=(5π/6)
n=3 x₉=(π/6)+(3π/3)=(7π/6)
n=4 x₁₀=(π/6)+(4π/3)=(9π/6)=(3π/2)= x₄
n=5 x₁₁=(π/6)+(5π/3)=(11π/3)
О т в е т. 0; π/2; π; 3π/2; 2π; π/6; 5π/6; 7π/6; 11π/6.