1, general formula: y=ax2+bx+c(a≠0).
2. Vertex: y = a (x-m) 2+k (a ≠ 0), where the vertex coordinate is (m, k) and the symmetry axis is a straight line x = m.
3. Intersection point: y = a (X-X 1) (X-X2) (A ≠ 0), where X 1 and X2 is the abscissa of the intersection point of parabola and x axis.
history
Around 480 BC, Babylonians and China had found the positive root of quadratic equation by collocation method, but did not put forward the general solution. Around 300 BC, Euclid proposed a more abstract geometric method to solve quadratic equations.
In the 7th century, Brahmagupta of India was the first person who knew how to use algebraic equations, which allowed positive and negative roots.
In 1 1 century, Elazemi of Arabia independently developed a set of formulas for finding positive solutions of equations. Abraham Bachirat (also known as Savosoda in Latin) introduced the complete solution of the quadratic equation of one variable to Europe for the first time in his book Liber embadorum.