U-shaped function

A U-shaped function is a mathematical concept where the graph of a relationship forms a shape similar to the letter "U." This means that as the input value increases, the output decreases initially, reaches a lowest point (the vertex), and then increases again. In real-world terms, it can describe situations like the balance of costs and benefits, where both very low and very high levels of a variable lead to poorer outcomes, while a moderate level produces the best result. Essentially, the function highlights that the relationship has two sides: decreasing and increasing, with a minimum point in between.