Quadratic Function Vertex Form Quiz a=+-1

This example demonstrates the effect of parameter a=+1 or a=-1 on the graph's opening direction in the vertex form of a quadratic function f(x)=a(x-h)^2+k. Key math concepts include quadratic functions, vertex form, opening direction, and axis of symmetry. GeoGebra commands used are Min, Max, RandomElement, If, Textfield to construct functions f, g, and dynamically adjust a via Slider, with results displayed in Textfield. Suitable for high school mathematics teaching to understand quadratic function properties and the role of parameter a.