https://pantip.com/topic/38221485/
code สำหรับปัญหานี้
https://www.wolframcloud.com/objects/sompob/test/pantip_01Nov18.nb Manipulate[ Show[ Graphics[{EdgeForm[Pink], FaceForm[Blue], Rectangle[{1 - Cos[-15 Degree], 0}, {x, x - (1 - Cos[-15 Degree])}]}], Graphics[{EdgeForm[LightBlue], FaceForm[Black], Rotate[Rectangle[{0, 0}], -15 Degree, {1, 0}], PlotRange -> {{-2, 2}, {-2, 2}} }], Graphics[ Text["Area of the Big Square:" <> ToString[(x - (1. - Cos[15 Degree]))^2/(0.5*Sin[15 Degree]* Cos[15 Degree])], {0.25, 1.5}]] ], {{x, 1.259, "side"}, 0.1, 2, 0.001} ]
