Problem 59

Question

\(59-60\) \(f, g,\) and \(f+g\) on a common screen to illustrategraphical addition. $$ f(x)=x, \quad g(x)=\sin x $$

Step-by-Step Solution

Verified
Answer
Graphically add function values to create a combined plot.
1Step 1: Identify Functions
We have two functions given: 1. \( f(x) = x \) which is a straight line through the origin with slope 1.2. \( g(x) = \sin x \) which is a sinusoidal function, periodic with amplitude 1.
2Step 2: Sketch the Graph of \(f(x)\)
The graph of \( f(x) = x \) is a straight line passing through the origin (0,0) with a slope of 1. It increases linearly as \( x \) increases.
3Step 3: Sketch the Graph of \(g(x)\)
The graph of \( g(x) = \sin x \) is a wave that oscillates between 1 and -1 with a period of \( 2\pi \). It starts from (0,0), rises to (\( \frac{\pi}{2}, 1 \)), falls back to (\( \pi, 0 \)), dips to (\( \frac{3\pi}{2}, -1 \)), and returns to (\( 2\pi, 0 \)).
4Step 4: Determine \(f(x) + g(x)\)
The new function is \( f(x) + g(x) = x + \sin x \). To sketch this, add the corresponding y-values of \( f(x) \) and \( g(x) \) at each point \( x \).
5Step 5: Sketch the Graph of \(f(x) + g(x)\)
The graph of \( f(x) + g(x) \) will be a combination of the linear increase from \( f(x) \) and the oscillations from \( g(x) \). It will appear as a sinusoidal wave that shifts upwards as \( x \) increases linearly.
6Step 6: Interpret the Resulting Graph
By graphically adding \( f(x) \) and \( g(x) \), the resulting curve illustrates how a linear trend can combine with periodic oscillations, showing both linear growth and wave-like features in the sum.

Key Concepts

Linear FunctionsSinusoidal FunctionsFunction Addition
Linear Functions
Linear functions are the simplest type of functions, represented as a straight line on a graph. In mathematical terms, a linear function can be expressed in the form \( f(x) = mx + b \), where \( m \) represents the slope of the line and \( b \) is the y-intercept.
For the function \( f(x) = x \), the slope \( m \) is 1, which indicates that for every unit increase in \( x \), \( y \) also increases by one unit. There is no y-intercept (\( b = 0 \)), so the line passes directly through the origin (0,0).
Linear functions are important in mathematics because they provide a straightforward way to model relationships where change happens at a constant rate.
  • They depict proportional relationships.
  • Graphically represented as straight lines.
  • Useful for understanding basic growth trends.
Sinusoidal Functions
Sinusoidal functions, like \( g(x) = \sin x \), are characterized by their wave-like patterns. These functions are defined by their amplitude, period, and phase shift. The amplitude is the peak value of the wave, which in \( g(x) = \sin x \) is 1, meaning the wave oscillates between 1 and -1.
The period, which is the distance required for the function to complete a full cycle, is \( 2\pi \) for the sine function. In simpler terms, a complete sine curve from start to finish, consisting of a rise and a fall, occurs between \( x = 0 \) and \( x = 2\pi \).
Sinusoidal functions are often used to model cyclic phenomena such as sound waves, light waves, and tides due to their repetitive nature.
  • They have a regular, repeating pattern.
  • Their graphs resemble smooth, continuous waves.
  • Essential for modeling periodic behaviors.
Function Addition
Function addition involves summing two or more functions to produce a new function. In the context of graphical addition, we visually add the values of two functions at each point \( x \) to create a third function. In this exercise, we add \( f(x) = x \) and \( g(x) = \sin x \) to form \( f(x) + g(x) = x + \sin x \), combining the linear and sinusoidal functions into a single graph.
This combined graph reflects both the linear growth of the straight line and the oscillating nature of the sine wave. The resulting function showcases how a base level (linear trend) can be modulated by periodic fluctuations.
  • Creates a new function through graphical addition.
  • Combines characteristics of different function types.
  • Helpful for understanding complex behavior arising from multiple influences.