# Quadratic Equations

By M. Bourne

A parabolic dish antenna uses the quadratic equation

Introduction to Quadratic Equations

Quadratic equations are used in many areas of science and engineering. The path of a projectile (e.g. a cannon ball) is (almost) parabolic, and we use a quadratic equation to find out where the projectile is going to hit. Also, parabolic antennas are another application.

Real mathematics is about **modelling** situations that occur naturally, and using the model to understand what is happening, or maybe to predict what will happen in future.

The quadratic equation is often used in modelling because it is a beautifully simple curve.

Related IntMath topics

The parabola is closely related to the quadratic equation

Complex Numbers arise out of the problem where we cannot find the square root of a negative number.

We can see quadratic equations used in integration by partial fractions

Curve sketching (an application of differentiation)

Areas under parabolic curves and Simpson's Rule (applications of integration)

Solving second-order homogeneous linear differential equations

Finding the intersection point of two circles

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