Contact us
Choose a category below so we can get back to you as quickly as possible.
sina+cosa=2/3兩邊平方 得到(sina+cosa)^2=(sina)^2+(cosa)^2+2sina cosa=1+sin 2a=4/9 所以sin 2a=-5/9 所以180°
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.