tan10°+tan50°+3tan10°tan50°的值为( ) A.-3 B.3 C.3 D.33
问题描述:
tan10°+tan50°+
tan10°tan50°的值为( )
3
A. -
3
B.
3
C. 3
D.
3
3
答
tan10°+tan50°+
tan10°tan50°
3
=tan(10°+50°)(1-tan10°tan50°)+
tan10°tan50°
3
=
(1-tan10°tan50°)+
3
tan10°tan50°
3
=
-
3
tan10°tan50°+
3
tan10°tan50°
3
=
.
3
故选:B.