Question

Write the quadratic formula and circle the part that is the discriminant.

Short answer

The quadratic formula is \(x = \frac{{-b \pm \sqrt{{b^2 - 4ac}}}}{2a}\) and the discriminant is \(b^2 - 4ac\).

Step-by-step solution

Write down the quadratic formula

The quadratic formula is written as \(x = \frac{{-b \pm \sqrt{{b^2 - 4ac}}}}{2a}\). This equation is used to find the solutions (or roots) of a quadratic equation of the form \(ax^2+bx+c=0\).

Highlight the Discriminant

The part of the quadratic formula that is the discriminant is \(b^2 - 4ac\). The discriminant is used to determine the types of roots for the equation.

Key concepts

Discriminant

The discriminant of a quadratic equation plays a crucial role in defining the nature of the equation's roots. It can be found in the quadratic formula under the square root sign and is given by the expression \(b^2 - 4ac\). The value of the discriminant provides important information about the characteristics of the roots:

• If the discriminant is positive (\(b^2 - 4ac > 0\)), the quadratic equation has two distinct real roots.
• If the discriminant is zero (\(b^2 - 4ac = 0\)), the equation has exactly one real root (also called a repeated or double root).
• If the discriminant is negative (\(b^2 - 4ac < 0\)), the equation has two complex roots which are conjugates of each other.

Understanding the discriminant is a powerful tool for anticipating the results of quadratic equations without even requiring to calculate the roots in detail.

Quadratic Equation Roots

The roots of a quadratic equation are the values of \(x\) that make the equation \((ax^2 + bx + c = 0)\) true. They are the points where the parabola, which is the graph of a quadratic equation, intersects the \(x\)-axis. To calculate these roots, one can apply the quadratic formula, \(x = \frac{{-b \pm \sqrt{{b^2 - 4ac}}}}{2a}\), where \(\pm\) denotes that there are potentially two solutions.

When applying the quadratic formula, after computing the discriminant, you proceed to include it within the quadratic formula. If the discriminant is non-negative, the equation yields real roots, which can be further calcualted to specific values. However, if the discriminant is negative, then the roots will be complex, which means they have an imaginary component and cannot be represented as points on the real number line.

These roots are not just numerical values, but they have substantial meanings in various contexts, such as physics for determining time of flight, in finance for calculating break-even points, and in geometry for finding the dimensions of geometric shapes.

Quadratic Equation

A quadratic equation is a second-degree polynomial equation in one variable typically written in the form \(ax^2 + bx + c = 0\), where \(a\), \(b\), and \(c\) are coefficients, and \(a \eq 0\). If \(a = 0\), the equation is not quadratic but linear. The standard form of a quadratic equation is essential for various methods of finding the roots, including factoring, completing the square, graphing, and using the quadratic formula.

The quadratic formula method is often the most reliable and widely used as it provides a systematic solution applicable to all forms of quadratic equations. In real-world scenarios, quadratic equations model various phenomena such as projectile motion, areas of shapes, and business profit calculations, demonstrating their significance beyond academic exercises.