Упростите ctg60-cos120
Ctg60° - cos120° = √3/3 + 1/2 = 2√3/6 + 3/6 = (2√3 + 3)/6
Ctg60-cos120=ctg60-cos(90+30)=ctg60-sin30=√3/3-1/2=(2√3-3)/6