Chapter 0: Problem 4
Use the quadratic formula to find the zeros of the functions. $$f(x)=\frac{1}{4} x^{2}+x+1$$
Short Answer
Expert verified
The zero of the function is \( x = -2 \).
Step by step solution
01
Identify Coefficients
For the quadratic equation in the standard form, identify the coefficients: \ The given function is \[ f(x) = \frac{1}{4}x^2 + x + 1 \] \( a = \frac{1}{4} \) \( b = 1 \) \( c = 1 \)
02
Write Down the Quadratic Formula
The quadratic formula to find the zeros of the function is: \[ x = \frac{{-b \pm \sqrt{{b^2 - 4ac}}}}{{2a}} \]
03
Substitute into the Quadratic Formula
Substitute the identified coefficients into the quadratic formula: \[ x = \frac{{-1 \pm \sqrt{{1^2 - 4 \cdot \frac{1}{4} \cdot 1}}}}{{2 \cdot \frac{1}{4}}} \] This simplifies to: \[ x = \frac{{-1 \pm \sqrt{{1 - 1}}}}{{0.5}} \] \[ x = \frac{{-1 \pm \sqrt{0}}}{{0.5}} \]
04
Solve the Equation
Since the discriminant is 0, the equation simplifies to: \[ x = \frac{{-1}}{0.5} \] \[ x = -2 \]
05
Conclusion
Thus, the quadratic function \[ f(x)=\frac{1}{4} x^{2}+x+1 \] has one real root: \[ x = -2 \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
zeros of a function
The zeros of a function are the values of x for which the function equals zero. When dealing with quadratic functions, these zeros are also referred to as roots or solutions of the equation. For a function like \[ f(x) = \frac{1}{4} x^2 + x + 1 \], finding the zeros involves solving the equation \[ \frac{1}{4} x^2 + x + 1 = 0 \]. This process helps us understand where the graph of the function intersects the x-axis. Solving for zeros is crucial because it provides insights into the behavior of the function, such as where it changes signs.
discriminant
The discriminant is a key part of the quadratic formula, recognizable in the expression under the square root: \[ b^2 - 4ac \]. It helps determine the nature of the roots of a quadratic equation. Depending on its value, we can identify:
- If the discriminant is positive, the equation has two distinct real roots.
- If it is zero, there is exactly one real root, as seen in our example with the function \[ f(x) = \frac{1}{4} x^2 + x + 1 \], which simplified to give \[ x = -2 \].
- If the discriminant is negative, the equation has no real roots, only complex ones.
solving quadratic equations
To solve quadratic equations, one common method is using the quadratic formula: \[ x = \frac{{-b \pm \sqrt{{b^2 - 4ac}}}}{{2a}} \]. This formula solutions are derived from the coefficients of the given quadratic function in the form \[ ax^2 + bx + c = 0 \]. Steps include:
- Identify the coefficients a, b, and c from the equation.
- Substitute these values into the quadratic formula.
- Calculate the discriminant \[ b^2 - 4ac \] and determine the nature of the roots.
- Solve for x by simplifying the expression.
quadratic function
A quadratic function is a second-degree polynomial function of the form \[ f(x) = ax^2 + bx + c \], where a, b, and c are constants and a ≠0. These functions have distinctive U-shaped graphs called parabolas, which can open upward or downward based on the sign of the coefficient a. Key features of quadratic functions include:
- The vertex, representing the highest or lowest point on the graph.
- The axis of symmetry, a vertical line through the vertex.
- The direction of the parabola's opening determined by the sign of a.