Помогите решить простые тригонометрические уравнения

1) tg(x+2)=0

2) 2 * sin3x+1=0

3) ctg (x+3) =0

4) cos x/2 - 0.5 = 0

 

1)tg(2+x)=0                                                   3) ctg(x+3)=0

x+2=пk                                                           x+3=пk

x= пk-2                                                           x=пk-3

2) 2sin3x+1                                                  4) cos x/2-0,5=0

2sin3x=-1                                                         cosx/2=1/2

sin3x=-1/2 ; это все делим на3                      x/2=+- arccos 1+2пk

x=(-1)k п/18+пk/3                                          x=+- arccos1+4пk