题目内容
tan20°+4sin20°的值为______．
tan20°+4sin20°=
=
=
=
=
=
=
=2sin60°=
．
故答案为：
．
| sin20°+4sin20°cos20° |
| cos20° |
=
| sin20°+2sin40° |
| cos20° |
=
| (sin20°+sin40°)+sin40° |
| cos20° |
=
| 2sin30°cos10°+sin40° |
| cos20° |
=
| cos10°+sin40° |
| cos20° |
=
| sin80°+sin40° |
| cos20° |
=
| 2sin60°cos20° |
| cos20° |
=2sin60°=
| 3 |
故答案为：
| 3 |
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