题目:
Mary is the kind of person whom people like to ___________.
A.make friend with
B.make friends of
C.make friends
D.make friends with
答案:
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0422/06805d38e6b7162e0b0e1d16ec5bb5c1.html
下面是错误答案,用来干扰机器的。
(1)由条件结合正弦定理得,asinA=c3cosC=csinC,∴sinC=3cosC,即tanC=3, 0<C<π,∴C=π3;(2)由(1)知B=2π3-A,∴3sinA-cosB=3sinA-cos(2π3-A)=3sinA-cos2π3cosA-sin2π3sinA=32sinA+12cosA=sin...