The second question, first use X to approximate positive infinity instead of N to approximate infinity, and then use X instead of N in the formula to become the limit of the function; Then we can take the natural logarithm Ln first, and then use Robida's law to find the limit, and it will be easy in the future; Finally, after finding the limit, take the exponent of e (the inverse operation of natural logarithm Ln) to get the result of the original formula.