3/14=(sin90°-x)/(sin120°-x)
3/14=(1-x)/(√3-x)
14(1-x)=3(√3-x)
14-14x=3√3-3x
11x=14-3√3
x=(14-3√3)/11
如果是sin(90°-x)和sin(120°-x)
3/14=sin(90°-x)/sin(120°-x)
3/14=(cosx-0)/(√3cosx/2+sinx/2)
3(√3cosx/2+sinx/2)=14cosx
3√3cosx/2+3sinx/2=14cosx
3sinx=(28-3√3)cosx
sinx/cosx=(28-3√3)/3
即tanx=(28-3√3)/3
所以x=arctan[(28-3√3)/3]