tanα/2=3,求tan(α-π/4)和6sinα-cosα/3sinα+4cosα

问题描述:

tanα/2=3,求tan(α-π/4)和6sinα-cosα/3sinα+4cosα

tanα/2=3tanα=2tanα/2/(1-tan²α/2)=2*3/(1-3²)=6/(-8)=-3/4tan(α-π/4)=(tanα-tanπ/4)/(1+tanαtanπ/4)=(tanα-1)/(1+tanα)=(-3/4-1)/(1-3/4)=(-7/4)/(1/4)=-7(6sinα-cosα)/(3sinα+4cosα)分...