导航 解：00an2X50tan300°=an60°3 (2)原式-sin10°cos10°c0s20°cos40° 2c0s10° sin20°cos20°cos40°= sin40°c0s40° 4c0s10° 8c0S10° sin80° c0s10° 1 16c0s10° 16c0S10° 16
导航 解:(1) 𝟐𝐭𝐚𝐧𝟏𝟓𝟎° 𝟏-𝐭𝐚𝐧𝟐 𝟏𝟓𝟎° =tan(2×150°)=tan 300°=-tan 60°=- 𝟑. (2)原式= 𝐬𝐢𝐧𝟏𝟎°𝐜𝐨𝐬𝟏𝟎°𝐜𝐨𝐬𝟐𝟎°𝐜𝐨𝐬𝟒𝟎° 𝟐𝐜𝐨𝐬𝟏𝟎° = 𝐬𝐢𝐧𝟐𝟎°𝐜𝐨𝐬𝟐𝟎°𝐜𝐨𝐬𝟒𝟎° 𝟒𝐜𝐨𝐬𝟏𝟎° = 𝐬𝐢𝐧𝟒𝟎°𝐜𝐨𝐬𝟒𝟎° 𝟖𝐜𝐨𝐬𝟏𝟎° = 𝐬𝐢𝐧𝟖𝟎° 𝟏𝟔𝐜𝐨𝐬𝟏𝟎° = 𝐜𝐨𝐬𝟏𝟎° 𝟏𝟔𝐜𝐨𝐬𝟏𝟎° = 𝟏 𝟏𝟔
(3):'sin50°(1+3tan10°)）=sin50°(1h3 010 导航 c0S10° =sin50°.cos10°+v3sin10° c0s10° 2×(停sn10+c0s10 =sin50° c0s10° =sin50° 2sin40° 2sin40°c0s40° sin80° c0s10° c0s10° c0s10° =1, sin80°V1+c0s20°=c0s10°V2c0s210°=V2c0s210°， :原式=1+c0s20° 2c0s210° V2c0s210° V2c0s210° =√2
导航 (3)∵sin 50°(1+ 𝟑tan 10°)=sin 50°·(1+ 𝟑 𝐬𝐢𝐧𝟏𝟎° 𝐜𝐨𝐬𝟏𝟎° ) =sin 50°· 𝐜𝐨𝐬𝟏𝟎°+ 𝟑𝐬𝐢𝐧𝟏𝟎° 𝐜𝐨𝐬𝟏𝟎° =sin 50°· 𝟐× 𝟑 𝟐 𝐬𝐢𝐧𝟏𝟎°+ 𝟏 𝟐 𝐜𝐨𝐬𝟏𝟎° 𝐜𝐨𝐬𝟏𝟎° =sin 50° 𝟐𝐬𝐢𝐧𝟒𝟎° 𝐜𝐨𝐬𝟏𝟎° = 𝟐𝐬𝐢𝐧𝟒𝟎°𝐜𝐨𝐬𝟒𝟎° 𝐜𝐨𝐬𝟏𝟎° = 𝐬𝐢𝐧𝟖𝟎° 𝐜𝐨𝐬𝟏𝟎° =1, sin 80° 𝟏 + 𝐜𝐨𝐬𝟐𝟎°=cos 10° 𝟐𝐜𝐨𝐬 𝟐 𝟏𝟎° = 𝟐cos2 10°, ∴原式= 𝟏+𝐜𝐨𝐬𝟐𝟎° 𝟐𝐜𝐨𝐬 𝟐 𝟏𝟎° = 𝟐𝐜𝐨𝐬 𝟐 𝟏𝟎° 𝟐𝐜𝐨𝐬 𝟐 𝟏𝟎° = 𝟐