Problem15

This is a math problem. If you can solve it, please comment your solution into the comment field or link your solution page URL in the comment field. I would check it.

The prepared solution file is linked on the below page (math-pro*.pdf). Since this original solution was already posted into @takashishinzato on Instagram, if you want to know about it, please check Instagram. If you can support this educational activity, please purchase it.