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中考试题常把一元二次方程与三角函数综合起来．解这类问题时要正确应用锐角三角函数的定义及有关性质，以及一元二次方程的有关知识．现以近两年的中考题为例，介绍这类问题的解题思路． 一、求锐角三角函数的值 例 １ 若 ａ为锐角，且 ｓｉｎ ａ是方程 ２ｘ２＋３ｘ－２＝０
The middle exam questions often synthesize quadratic equations with trigonometric functions. To solve this type of problem, we must correctly apply the definition and related properties of the acute-angle trigonometric function, and the relevant knowledge of the one-dimensional quadratic equation. Take the recent two years of exam questions as an example to introduce the problem-solving ideas of this type of problem. First, find the value of the acute angle trigonometric function Example 1 If a is an acute angle, and sin a is the equation 2x2+3x-2=0