题目
| sin35°−sin25° |
| cos35°−cos25° |
提问时间：2021-03-04
答案
原式=
=
=
=-
| sin(30°+5°)−sin(30°−5°) |
| cos(30°+5°)−cos(30°−5°) |
=
| sin30°cos5°+cos30°sin5°−(sin30°cos5°−cos30°sin5°) |
| cos30°cos5°−sin30°sin5°−(cos30°cos5°+sin30°sin5°) |
=
| 2cos30°sin5° |
| −2sin30°sin5° |
=-