在△ABC中,角A,B,C的对边分别为a,b,c,且cos(A-B)cosB-sin(A-B)sin(A+C)=-3/5(1)求sinA的值(2)若a=4根号2,b=5,求向量BA在向量BC方向上的投影
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/19 04:51:20
![在△ABC中,角A,B,C的对边分别为a,b,c,且cos(A-B)cosB-sin(A-B)sin(A+C)=-3/5(1)求sinA的值(2)若a=4根号2,b=5,求向量BA在向量BC方向上的投影](/uploads/image/z/3690074-2-4.jpg?t=%E5%9C%A8%E2%96%B3ABC%E4%B8%AD%2C%E8%A7%92A%2CB%2CC%E7%9A%84%E5%AF%B9%E8%BE%B9%E5%88%86%E5%88%AB%E4%B8%BAa%2Cb%2Cc%2C%E4%B8%94cos%28A-B%29cosB-sin%28A-B%29sin%28A%2BC%29%3D-3%2F5%EF%BC%881%EF%BC%89%E6%B1%82sinA%E7%9A%84%E5%80%BC%EF%BC%882%EF%BC%89%E8%8B%A5a%3D4%E6%A0%B9%E5%8F%B72%2Cb%3D5%2C%E6%B1%82%E5%90%91%E9%87%8FBA%E5%9C%A8%E5%90%91%E9%87%8FBC%E6%96%B9%E5%90%91%E4%B8%8A%E7%9A%84%E6%8A%95%E5%BD%B1)
xTN@K<L$2|Il6PT,hKRx9$ER""JIafg_;QJ*UT+ܹsguz)C>5.5;g{UHvQ 7ܱr&"划PWlx6SRj`Ɂ]tR6dvdJ5!?l
̬sw!Y/vZ{#%՟2H2c`a%8Prn|B߇`+Qq5Јl][ wp/#]A^hDw^
#$gՈ4+X&3=r(AaKrVdf p0CsHk\kBtʅ_nJFr?˱g,d^Fn:J6g+*+ ǂ7rOiJG2AAUO