已知a,b是锐角,且满足sinb=sinacos(a+b),若a+b=π/4,则tanb=
问题描述:
已知a,b是锐角,且满足sinb=sinacos(a+b),若a+b=π/4,则tanb=
答
sinb=sina / √2
√2*sinb=sina=sin(π/4-b)=cosb/√2-sinb/√2
3sinb=cosb
tanb=1/3