Final answer:
A quadratic model needs to exist according to a calculator when the quadratic equation has real roots. The discriminant of the equation can help determine if it has real roots. Additionally, a calculator with graphing capabilities can help visualize the quadratic function.
Step-by-step explanation:
A quadratic model needs to exist according to a calculator when the quadratic equation has real roots. In other words, the equation needs to have solutions that are both real and not imaginary numbers. This ensures that the calculator can accurately compute and graph the quadratic function.
For example, consider the quadratic equation y = ax^2 + bx + c. If the discriminant (b^2 - 4ac) is greater than or equal to zero, then the equation has real roots and a quadratic model can be created on a calculator.
Additionally, a calculator with graphing capabilities is helpful for visualizing the quadratic function on a graph.