Quadratic graphs

Quadratic graphs

  • A quadratic graph is a curve called a parabola and its equation is in the form of y = ax² + bx + c, where a, b, and c are constants.
  • The value of ‘a’ determines the direction and width of the parabola. If ‘a’ is positive, the graph opens upwards, and if ‘a’ is negative, the graph opens downwards. Larger a values make the graph narrower and smaller a values make the graph wider.
  • The value ‘c’ in the equation is the y-intercept, which is the point where the graph crosses the y-axis.
  • ‘b’ influences the position of the axis of symmetry, a vertical line passing through the vertex of the parabola.
  • The solutions or roots of the quadratic equation are the x-coordinates where the graph touches or crosses the x-axis. These points are also called ‘zeros’ or ‘x-intercepts’.
  • You can find the x-intercepts by setting y = 0 and solving the resulting equation.
  • The axis of symmetry is given by the formula x = -b/2a.
  • The turning point or vertex of the parabola can be found using the axis of symmetry. Substitute the x value from the axis of symmetry into the quadratic equation to find the y-coordinate of the vertex.
  • Quadratics can have two real roots (the graph crosses the x-axis at two distinct points), one real root (the graph touches the x-axis at a single point), or no real roots (the graph doesn’t intersect with the x-axis). The term “discriminant” (b² - 4ac) can determine the number of roots.
  • Quadratic graphs have a line of symmetry half way between the two roots.
  • Completing the square is a method to rewrite the quadratic equation in the form (x-h)²=k, which shows you the vertex (h, k) directly.
  • Quadratic graphs are important in understanding many natural phenomena and are widely used in physics, engineering, and business economics.