问题
选择题
|
答案
=sin50°(cos10°+
sin10°)3 sin80°
=sin50°[2sin(10°+30°)] sin80°
=2cos40°sin40° sin80°
=1sin80° sin80
故选C.
|
=sin50°(cos10°+
sin10°)3 sin80°
=sin50°[2sin(10°+30°)] sin80°
=2cos40°sin40° sin80°
=1sin80° sin80
故选C.