(asinπ/5 +bcosπ/5)/(acosπ/5 -bsinπ/5)=tan8π/15,则b/a等于 A.√3 B.√3/3 C.-√3 D.-√3/3
问题描述：
(asinπ/5 +bcosπ/5)/(acosπ/5 -bsinπ/5)=tan8π/15,则b/a等于 A.√3 B.√3/3 C.-√3 D.-√3/3
(asinπ/5 +bcosπ/5)/(acosπ/5 -bsinπ/5)=tan8π/15,则b/a等于
A.√3B.√3/3C.-√3D.-√3/3
答
(asinπ/5 +bcosπ/5)/(acosπ/5 -bsinπ/5)=tan8π/15(tanπ/5+b/a)/(1-b/atanπ/5)=tan(π/5+π/3)(tanπ/5+b/a)/(1-b/atanπ/5)=(tanπ/5+tanπ/3)/(1-tanπ/5tanπ/3)(tanπ/5+b/a)/(1-b/atanπ/5)=(tanπ/5+√3...