use trigonometric ratios of special angles to find the value of :
(sin 30° + sin 45 °) [tan 60° + (1/tan 30° )}
Easy maths question!?
2016-05-13 9:43 am
回答 (2)
2016-05-13 2:13 pm
(sin 30° + sin 45 °) [tan 60° + (1/tan 30° )}
=(0.5+√2/2)[√3+tan (90-30)]
=(0.5+√2/2)[√3+tan 60°]
=(0.5+√2/2)(2√3)
=(1+√2)(√3)
=√3 +√6
=(0.5+√2/2)[√3+tan (90-30)]
=(0.5+√2/2)[√3+tan 60°]
=(0.5+√2/2)(2√3)
=(1+√2)(√3)
=√3 +√6
2016-05-13 11:40 am
Sol
Sin30°=1/2
Sin 45°=√2/2
Tan 60°=√3
1/San30°=Cot30°=Tan60°=√3
(Sin 30°+sin 45°)/[Tan 60°+(1/Tan 30°)]
=(1/2+√2/2)/(√3+√3)
=(1+√2)/(4√3)
=√3 (1+√2)/[√3 (4√3)]
=(√3+√6)/12
Sin30°=1/2
Sin 45°=√2/2
Tan 60°=√3
1/San30°=Cot30°=Tan60°=√3
(Sin 30°+sin 45°)/[Tan 60°+(1/Tan 30°)]
=(1/2+√2/2)/(√3+√3)
=(1+√2)/(4√3)
=√3 (1+√2)/[√3 (4√3)]
=(√3+√6)/12
收錄日期: 2021-04-18 14:50:08
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160513014352AARRpYf