解三角形是高中的必修内容,也是高考的重要内容。因为三角形和三角函数的联系非常紧密,问题设置多具有灵活的特点,所以在高考命题中备受命题人的青睐。据参加高考的同学反映,三角形问题的解答没有清晰地思路,成了许多同学的拦路虎,现以几道高考题目为例来说明一下解三角形问题的解题方法,以期对学生有所帮助。【典例1】在△ABC中,内角A、B、C的对边长分别为a、b、c,已知a2-c2=2b,且sin Acos C=3cos Asin C,求b. Solution triangle is compulsory content of high school, but also an important part of college entrance examination. Because of the triangle and trigonometric function is very close, the problem set more flexible features, so much proposition in the college entrance examination proposition of all ages. According to the college entrance examination reflects the students, the answer to the triangle problem does not have a clear idea, has become a stumbling block to many students, is now taking several college entrance examination questions as an example to illustrate how to solve the triangle problem solving method, with a view to help students. [Example 1] In ABC, the opposite sides of the internal angles A, B and C are respectively a, b and c, and it is known that a2-c2 = 2b and sin Acos C = 3cos Asin C, and find b.