20 18, Question 2 of Mathematics for Postgraduate Entrance Examination 19
I don't think this makes sense. The purpose is to consider whether it is less likely if all three numbers are not needed. The calculation method is the same as above, but it can be calculated quickly. Looking at the law of the above formula, it is easy to find that if x=0, less π in the denominator is the minimum area; If y=0, then subtracting 4 from the denominator is the minimum area; If z=0, then subtracting 3√3 from the denominator is the minimum area.