17) ctq²(2x -π/3) =3;
1+cos(4x -2π/3) =3(1-cos(4x- 2π/3) ;
cos(4x - 2π/3) = 1/2 ;
4x -2π/3 = π/3 +2π*k ;
4x = π +2π*k;
x₁ =π/4 +π/2*k ,k∈ Z ;
4x -2π/3 = - π/3 +2π*k ;
4x = π/3 +2π*k ;
x₂=π/12 +π/2*k , k∈ Z .
18) tq²(3x+π/2) =1/3 ;
ctq²3x =1/3 ;
3(1+cos6x) =1-cos6x ;
cos6x = -1/2 ;
6x = (+/-)(π -π/3) +2π*k ;
x = (+/-)π/9 + π*k/3 , k∈ Z .
19)
3cos²x -5cosx =0;
3cosx(cosx -5/3) =0 ;
cosx=0 ;
x=π/2 +π*k , k∈ Z.
cosx =5/3 >0. не имеет решения.
20) |sin3x| =1/2;
a) sin3x = -1/2;
3x₁ =(-1)^(k+1)*π/6 + π*k , k∈ Z.
x₁ =(-1)^(k+1)*π/18 + π/3*k , k∈ Z.
b) sin3x = 1/2;
3x₂ =(-1)^k*π/6 + π*k , k∈ Z.
x₂ =(-1)^k*π/18 + π/3*k , k∈ Z.
1 рад ~ 58°
136°≈2.345 рад
127°≈2.19 рад
20°≈0.345 рад
54°≈0.931 рад
<span> (x-3)^2-(x-1)(x+1)+6x=</span>
A) a^2 + 6a + 9
б) 4а^2 - 4аб + б^2
Х не=0; умножим на х правую и левую ча.ти уравнения:3-5х+8=2х; 2х+5х=11; 7х=11; х=11/7; х=1и4/7)))))) эs не печатает