java验证sin(x)在0到pi的积分等于2

Question

java验证sin(x)在0到pi的积分等于2

Answer 1

public class Test {

    public static void main(String[] args) {
        double pi = 3.1415926;//定义π 
        
        int n = 10000;//把积分区间分成n份 ,n越大值积分越接近实际值
        double dx = (pi - 0) / n;//每一小份长度 
        
        double sum = 0.0;//积分
        //累计每个矩形的面积和，高为sin(x);
        for (int i = 1; i <= n; i++) {
            double height = Math.sin(i * dx);
            sum += dx * height;
        }
        
        System.out.println(sum);
    }
}