sin50°(1+√3tan10°)的值 我解得自己也看不懂,
问题描述:
sin50°(1+√3tan10°)的值 我解得自己也看不懂,
答
度我省略了,打起来复杂
原式=sin50(1+tan10tan60)
=sin50(tan60-tan10)/tan50 .......(正切差角公式)
=cos50(3^0.5-tan10)
=cos50(3^0.5 cos10-sin10)/cos10
=cos50sec10 -2sin(10-60) ........(辅助角公式)
=2sin50cos50sec10
=sin100/cos10=1
答
sin50°(1+√3tan10°)=sin50°(1+√3sin10°/cos10°)=sin50°(cos10°+√3sin10°)/cos10°=2sin50°sin(30°+10°)/cos10°=2sin50°sin40°/cos10°=2cos40°sin40°/cos10°=sin80°/cos10°=cos10°/cos10°=1...