sina+cosa=根号2 两边平方得：1+2sinacosa=22sinacosa=1sinacosa=1/2>0所以,sina和cosa同号(sina-cosa)²=1-2sinacosa=1-1=0sina=cosatana=1tan(a+π/3)=(tana+tanπ/3)/(1-tanatanπ/3）=(1+√3)/(1-√3)=(1+√...谢谢谢啦