问题
解答题
化简[2sin500+sin100(1+
|
答案
原式=[2sin50°+sin10°（1+
）]
sin10°3 cos10° 1+cos200
=（2sin50°+sin10°•
）cos10°+
sin10°3 cos10° 1+cos200
=（2sin50°+2sin10°•
）sin(10°+30°) cos10° 1+cos200
=
•2sin50°cos10°+2sin10°sin40° cos10° 1+cos200
=2cos（40°-10°）•
cos10°2 cos10°
=2cos30°×2
=
．6