论文部分内容阅读
在各级各类的考试中，出现了一类如下所列的三角题：１．求ｓｉｎ２１０°＋ｃｏｓ２４０°＋ｓｉｎ１０°ｃｏｓ４０°的值．（高中《代数》上册必修第２３３页例１９）２．求ｃｏｓ２７３°＋ｃｏｓ２４７°＋ｃｏｓ４７°ｃｏｓ７３°的值．（１９８７年江苏青少年夏令...
In all types of examinations, there are a series of triangular questions listed below: 1. Find the value of sin210°+cos240°+sin10°cos40°. (High School “Algebra” Volume 1 of the compulsory book page 233 Example 19) 2. Find the value of cos273°+cos247°+cos47°cos73°. (1987 summer youth in Jiangsu province...