cos(60+x)cosX - sin(60+x)sinX = cos(60)cosX + cosXsin(60) - sin(60)sinX - cosXsinX = 1/2 cosX - √3/2 sinX - √3/2 cosX - 1/2 sinX = 1/2 (cosX - √3sinX) - √3/2 cosX = 1/2 (cosX - √3sinX) - 1/2 2√3/3 cosX = 1/2 (cosX - √3sinX) - √3/3 cosX = (1/2 - √3/3) cosX - 1/2 √3sinX = (3 - 2√3) / 6 cosX - √3/2 sinX = (3 - 2√3)cosX/6 - √3sinX/2.