tan(∝+B)=2/5tan(B-丌/4)=1/4则tan(∝+丌/4)=
问题描述:
tan(∝+B)=2/5tan(B-丌/4)=1/4则tan(∝+丌/4)=
答
已知:tan(α+β)=2/5,tan(β - π/4)=1/4,那么:
tan(α + π/4)
=tan[(α+β) - (β - π/4)]
=[tan(α+β) - tan(β - π/4)]÷[1 + tan[(α+β)tan(β - π/4)]
=(2/5 - 1/4)÷(1+ 2/5 * 1/4)
=(3/20)÷(22/20)
=3/22