Answer 1

х-1=+- пи3 +2пиn х= +- пи3 +2пи n+1

Answer 2

cos(x-1)=0,5; x-1=±arccos0,5 + 2πn, n∈Z$ x-1=±π/3 +2πn, n∈Z; x=π/3 + 1 + 2πn, n∈Z