tan(2*arctan(1/5)),tan(4*arctan(1/5)) https://www.wolframalpha.com/input?key=&i=tan%282*arctan%281%2F5%29%29%2Ctan%284*arctan%281%2F5%29%29&lang=ja 別の形
tan(2*arctan(1/5)),tan(4*arctan(1/5))
https://www.wolframalpha.com/input?key=&i=tan%282*arctan%281%2F5%29%29%2Ctan%284*arctan%281%2F5%29%29&lang=ja
別の形