已知tan a=-1/3,求4sin a-2cos a/5cos a+3sin a=_数学解答

已知tan a=-1/3,求4sin a-2cos a/5cos a+3sin a=

人气：134 ℃　时间：2019-11-07 13:04:37

解答

(4sin a-2cos a)/(5cos a+3sin a)=(4tana-2)/(5+3tana)=(-4/3-2)/[5+3(-1/3)]
=(-10/3)/4=-10/12=-5/6