acar 1) sinx=-2
x=(-1)ⁿarcsin(-2)+πn, n∈Z

2) sin2x=-√3/2
x=(-1)ⁿ arcsin(-√3/2)+πn , n∈Z
x=-( (-1)ⁿ  *π/3)+πn , n∈Z

3)2cosx=√2
cosx=√2/2
x=+-arccos(√2/2)+2πn , n∈Z
x=+-π/4+2πn , n∈Z

4) cos5x=0
5x=π/2+πn , n∈Z
x=π/10+πn/5 , n∈Z

5) tg2x=-1/√3
x=-arctg(1/√3)+πn , n∈Z
2x=-π/6++πn , n∈Z
x=-π/12+πn/2 , n∈Z