There are two math formulas in this double bubble map, which are the Aparabola and the square root function. They have the same functions, the same origin, and range. But as for the differences, the Aparabola, it is uesed to descrease and increase function, and the square root function only used for incereasing function. As for the domian, the Aparabola is all reals, but the square root function greater. Check more details from this double bubble map.