cos150°的值等於多少 cos150°等於幾分之幾
cos150°=-√3/2。cos150°=cos(120°+30°)=cos120°cos30°-sin120°sin30°=(-1/2)x√3/2-√3/2x1/2=-√3/4-√3/4=-(√3+√3)/4=-2√3/4=-√3/2。常見特殊角的函式值1、sin30°=1/22、cos30°=(√3)/23、sin45°=...
cos150°=-√3/2。cos150°=cos(120°+30°)=cos120°cos30°-sin120°sin30°=(-1/2)x√3/2-√3/2x1/2=-√3/4-√3/4=-(√3+√3)/4=-2√3/4=-√3/2。常見特殊角的函式值1、sin30°=1/22、cos30°=(√3)/23、sin45°=...