Chapter 7: Problem 29
Solve the given quadratic equations using the quadratic formula. If there are no real roots, state this as the answer. Exercises \(3-6\) are the same as Exercises \(13-16\) of Section 7.2. $$0.29 Z^{2}-0.18=0.63 Z$$
Short Answer
Expert verified
The solutions are approximately \(Z_1 = 2.4281\) and \(Z_2 = -0.2557\).
Step by step solution
01
Rearrange the Equation
The original equation given is \(0.29 Z^2 - 0.18 = 0.63 Z\). First, rearrange the equation to match the standard form of a quadratic equation, \(aZ^2 + bZ + c = 0\). Move all terms to one side: \(0.29 Z^2 - 0.63 Z - 0.18 = 0\).
02
Identify Coefficients
Identify the coefficients \( a \), \( b \), and \( c \) from the rearranged equation \(0.29 Z^2 - 0.63 Z - 0.18 = 0\). So, \(a = 0.29\), \(b = -0.63\), and \(c = -0.18\).
03
Apply the Quadratic Formula
The quadratic formula is given by \(Z = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\). Substitute \(a = 0.29\), \(b = -0.63\), and \(c = -0.18\) into the formula.
04
Compute the Discriminant
Calculate the discriminant part of the formula: \(b^2 - 4ac\). Substitute the values to get \((-0.63)^2 - 4 \times 0.29 \times (-0.18)\). First calculate \( (-0.63)^2 = 0.3969\), and \( 4 \times 0.29 \times (-0.18) = -0.2088\). Thus, the discriminant is \(0.3969 + 0.2088 = 0.6057\).
05
Evaluate the Square Root of the Discriminant
Compute the square root of the discriminant: \(\sqrt{0.6057}\). After calculation, \(\sqrt{0.6057} \approx 0.7783\).
06
Solve Using the Quadratic Formula
Substitute back into the quadratic formula: \(Z = \frac{-(-0.63) \pm 0.7783}{2 \times 0.29}\). Simplify to get \(Z = \frac{0.63 \pm 0.7783}{0.58}\).
07
Calculate the Two Possible Solutions
For the plus case, calculate \(Z_1 = \frac{0.63 + 0.7783}{0.58}\) which simplifies to approximately \( Z_1 = 2.4281\). For the minus case, calculate \(Z_2 = \frac{0.63 - 0.7783}{0.58}\) which simplifies to approximately \( Z_2 = -0.2557\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Formula
When faced with a quadratic equation of the form \(aZ^2 + bZ + c = 0\), the quadratic formula is your go-to tool for finding solutions. This magical formula provides the roots or solutions of any quadratic equation and is written as:
In cases where the discriminant is negative, you'll find imaginary roots.
Just like that, it gives you a reliable way to solve any quadratic equation, every time.
- \(Z = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)
- \(b\) is the coefficient of the linear term, \(Z\).
- \(a\) is the coefficient in front of the quadratic term, \(Z^2\).
- \(c\) is the constant term.
In cases where the discriminant is negative, you'll find imaginary roots.
Just like that, it gives you a reliable way to solve any quadratic equation, every time.
Discriminant
The discriminant is an essential component in understanding whether a quadratic equation has real solutions. It is the part of the quadratic formula located under the square root:
This value tells us different things based on its result:
- \(b^2 - 4ac\)
This value tells us different things based on its result:
- If it is positive, there will be two distinct real roots.
- If it equals zero, expect one real but repeated root.
- If it is negative, then the equation has no real roots (instead, you will get complex solutions).
- Calculate \((-0.63)^2 - 4 \times 0.29 \times (-0.18) = 0.6057\).
- Since 0.6057 is positive, there are two real roots, indicating a graph crossing the Z-axis at two points.
Coefficients Identification
Successfully solving a quadratic equation requires pinpointing each term's coefficient in the expression \(aZ^2 + bZ + c = 0\). Let's take a closer look at each one:
In the given exercise, properly identifying these coefficients is crucial:
- \(a\) represents the coefficient of the \(Z^2\) term.
- \(b\) is the coefficient attached to the \(Z\) term.
- \(c\) is the constant or the term independent of \(Z\).
In the given exercise, properly identifying these coefficients is crucial:
- With the equation \(0.29Z^2 - 0.63Z - 0.18 = 0\), we find that \(a = 0.29\), \(b = -0.63\), and \(c = -0.18\).