*11.1-1 矩形區域之雙重積分

課本圖3，4，5 參考圖

https://www.geogebra.org/m/rwcrs3yv

https://www.geogebra.org/m/jcmc66j3

http://dmentrard.free.fr/GEOGEBRA/Maths/Export5/Doubinteg1MD.html

課本圖2參考圖https://www.geogebra.org/m/deu55wzs

https://www.geogebra.org/m/nddz76ua