cos a=3/5 a属于(0.π/2)求1.sin(a-π/3)的值 2.求tan 2a

问题描述:

cos a=3/5 a属于(0.π/2)求1.sin(a-π/3)的值 2.求tan 2a

1.sina=4/5
sin(a-π/3)=sinacosπ/3-cosasinπ/3=(4-3根号下3)/10
2.tana=4/3
tan2a=2tana/(1-tana*tana)=-24/7