在vb/vc中调用mathlualib.dll中的自定义API计算一些泛函的值，如计算定积分∫[a->b]f(x)dx，计算数项级数∑[n=1->100]f(n)≈∑[n=1->+∞]f(n)，计算函数项级数∑[n=1->100]f(n,x)≈∑[n=1->+∞]f(n,x)，计算一阶ODEy =fsxy(x,y),y(x_0)=y_0中的y(x),……泛函的自变量在Lua文件里面输入。注意：请不要改变Lua中的函数名fun(x)，fan(n)，fsx(x)，fanx(n,x)，fsxy(x,y)，这几个泛函自变量的函数名和原型在mathlualib.dll中的自定义API中要经常用到。-In vb/vc call mathlualib.dll calculate some functional value, such as calculating the definite integral ∫ [a->　b] f (x) dx, calculate a number of series Σ [n = 1->　100] f (n ) ≈ Σ [n = 1-> + ∞] f (n), calculate the function key series Σ [n = 1->　100] f (n, x) ≈ Σ [n = 1-> + ∞] f ( n, x), calculate the first order ODEy　 = fsxy (x, y), y (x_0) = y_0 of y (x), ... ... functional of the independent variables entered in the Lua files inside. Note: Please do not change the function name in Lua fun (x), fan (n), fsx (x), fanx (n, x), fsxy (x, y), these functional prototype of the independent variables in mathlualib . dll in custom API to be frequently used.