/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 59 The equation \(x^{2}=2^{x}\) has... [FREE SOLUTION] | 91Ó°ÊÓ

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The equation \(x^{2}=2^{x}\) has three solutions: \(x=2, x=4,\) and one other. Estimate the third solution as accurately as you can by graphing.

Short Answer

Expert verified
The third solution is approximately x=0.76.

Step by step solution

01

Understand the Equation

The equation given is a transcendental equation, which is a combination of an exponential function and a polynomial function: \(x^{2} = 2^{x}\). We are searching for the values of \(x\) that satisfy this equation.
02

Known Solutions

We are given that two of the solutions are \(x = 2\) and \(x = 4\). This means that when we plug these values into the equation, it holds true: \(2^{2} = 2^{2}\) and \(4^{2} = 2^{4}\).
03

Graph the Functions

To find the third solution, graph the functions \(y_1 = x^{2}\) and \(y_2 = 2^{x}\) on the same set of axes. Look for their points of intersection, which are the solutions to the equation.
04

Identify Intersections

The points where the graphs intersect represent solutions to the equation. The graphs intersect at \((2, 4)\) and \((4, 16)\), confirming the known solutions. Look for another point of intersection besides \(x=2\) and \(x=4\).
05

Estimate the Third Solution

Based on the graph, identify the x-value of the third intersection point between \(y_1 = x^2\) and \(y_2 = 2^x\). This point will likely occur between x=0 and x=1.
06

Refine the Estimate Using Graphing Tools

Zoom in on the graph between x=0 and x=1 to better estimate the x-coordinate of the intersection point. The intersection is around approximately x=0.76.
07

Verify the Estimate

Double-check this estimate by evaluating \(x^{2}\) and \(2^{x}\) around \(x \approx 0.76\) to ensure that they are approximately equal.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Exponential Function
An **exponential function** is a mathematical expression where a constant base is raised to a varying exponent. The form of a simple exponential function is \(f(x) = a^x\), where \(a\) is a positive constant and \(x\) is the exponent. In this exercise, the function \(y_2 = 2^x\) represents our exponential function.
What makes exponential functions unique is their characteristic growth pattern. For instance:
  • Exponential functions increase (or decrease) rapidly compared to polynomial functions.
  • Their graphs showcase a rising slope as \(x\) becomes larger, assuming the base \(a\) is greater than 1.
In this situation, the base is 2, so as \(x\) increases, so does the value of \(2^x\). Understanding this growth behavior helps visualize the nature of the solution where \(y_2 = 2^x\) intersects with a polynomial function.
Polynomial Function
A **polynomial function** consists of terms that are all multiples of the variable raised to a non-negative integer power. The standard form is \(f(x) = a_nx^n + a_{n-1}x^{n-1} + \, ... \, + a_1x + a_0\). The function \(y_1 = x^2\) is a simple polynomial function of degree 2 (a quadratic function).
Here are some key characteristics of polynomial functions:
  • They usually exhibit smooth, continuous curves in graphical representations.
  • Depending on the highest degree, they can have a variety of shapes and number of intersections with other functions.
This exercise involves examining \(x^2\), which is particularly simple:
  • The graph of \(x^2\) is a parabola opening upwards because the leading coefficient is positive.
  • Its intersection behavior with an exponential function will often depend on the degree of the polynomial and the growth rate of the exponential function.
Knowing these characteristics aids in predicting where the polynomial and exponential graphs might meet.
Graphing Intersections
**Graphing intersections** is a common method for solving equations, especially when they involve functions that aren't easily solved algebraically. For the equation \(x^{2} = 2^{x}\) given here, we can graph each side of the equation as separate functions: \(y_1 = x^2\) and \(y_2 = 2^x\), then identify where these graphs intersect.
This approach to finding solutions provides multiple advantages:
  • It offers a visual representation of where the functions are equal.
  • It can help estimate solutions when exact computation is challenging.
To locate intersections accurately:
  • Graph both functions on the same axes using graphing tools.
  • Look for points where both graphs meet or cross each other.
  • These intersection points correspond to solutions of the equation.
In this problem, since manual calculation was complex, using a graphing tool allowed us to zoom between \(x=0\) and \(x=1\) to find an approximate solution for the third intersection point, fully utilizing the strength of graphing techniques to estimate it as \(x \approx 0.76\).

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