若a是锐角,且sin(x-π/6)=1/3,则cosx等于?

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/18 17:33:14
若a是锐角,且sin(x-π/6)=1/3,则cosx等于?
x){ѽ4ٌ/Lx|ΓS34*t7i<혙_\|m]}6IE$/!&d%@vP Rq g/xcHقO*tL{ig=OM1*k[X( ֯a1LPSF 1 0}O'.B̂

若a是锐角,且sin(x-π/6)=1/3,则cosx等于?
若a是锐角,且sin(x-π/6)=1/3,则cosx等于?

若a是锐角,且sin(x-π/6)=1/3,则cosx等于?
sin(x-π/6)=sinx*cosπ/6-cosx*sinπ/6=1/3,因为cosx=根号1-sin^2x,化简前式得,4cos^2x+4/3cosx-23/9=0解得cosx=(2根号6-1)/6

图呢