原理就是向一个定积分规定的区域内随机投入无数点，统计投入在函数曲线与坐标轴之间的点数比总点数乘此块区域面积就是积分-Principle is the random input to the area within a definite integral requirement many points, statistical input in the function of the number of points between the curve and axis than the tota

该函数返回值为积分结果，形参a,b分别为积分上下限，fun是被积函数。该函数用来求积分值。-This function returns a value of the integration result, parameters a, b is the integral upper and lower limits, respectively, fun is the plot function. This function is used to find the integral value