Problem 29 - BIG IDEAS MATH Algebra 2: Common Core Student Edition 2015

Question

\(g(x)=4 \tan x\)

Step-by-Step Solution

Answer

The function \(g(x)=4 \tan x\) is a standard tangent function scaled vertically by a factor of 4. Thus, the values of \(g(x)\) are 4 times the corresponding values of \(\tan x\), and it reaches four times higher in the positive direction and four times lower in the negative direction compared to \(\tan x\). The function has a period of \(\pi\) and vertical asymptotes at \(x = (n+\frac{1}{2})\pi\).

Step 1: Understanding the Function

Identify that \(\tan x\) is a periodic function with a period of \(\pi\). This means that it repeats its values every \(\pi\) units. The tangent function also has vertical asymptotes at \(x = (n+\frac{1}{2})\pi\) where \(n\) is any integer.

Step 2: Consider the Scalar

Next, consider the scalar multiplication of the tangent function by \(4\). This doesn't change the period of the function or the locations of the asymptotes. However, it does change the amplitude, i.e., it scales the function in the vertical direction. In this case, all values of the function will be 4 times the corresponding values of the regular tangent function.

Step 3: Graph the Function

To complete the problem, you can plot the function \(g(x)\) on a graph. The range of values for \(x\) can be from \(-2\pi\) to \(2\pi\). The function will be similar to the regular tangent function except it will reach higher peaks and lower valleys due to the scalar multiplication by 4.

Key Concepts

Periodic Function

Periodic functions are fundamental in mathematics because they have values that repeat at regular intervals. The tangent function, written as \( \tan x \), is a standard periodic function with a period of \( \pi \). This means that every \( \pi \) units along the x-axis, the tangent function repeats its pattern. Understanding this periodic nature is crucial when analyzing trigonometric functions, as the repetitiveness helps in predicting and calculating values across different cycles. This predictability is particularly helpful when solving equations and modeling real-world scenarios where cycles or patterns are present.

Tangent Function

The tangent function is one of the basic trigonometric functions and is represented by \( \tan x \). It is defined as the ratio of the sine and cosine functions: \( \tan x = \frac{\sin x}{\cos x} \). Unlike the sine and cosine functions, which have a range between -1 and 1, \( \tan x \) has a range of all real numbers, implying it can take infinitely large or small values. The tangent function is particularly distinct because it has vertical asymptotes, which occur due to the cosine function in the denominator equaling zero. These asymptotes occur every \((n+\frac{1}{2})\pi\), where \(n\) is an integer. This leads to breaks in the graph and infinite limits at these points, making its graphical representation unique.

Vertical Asymptotes

Vertical asymptotes in the graph of a function are lines where the function tends towards infinity. For the tangent function \(\tan x\), vertical asymptotes occur where the function is undefined due to the cosine function in its denominator becoming zero. Specifically, vertical asymptotes occur at \(x = (n+\frac{1}{2})\pi\) where \(n\) is any integer, causing the graph of \(\tan x\) to break and appear disconnected at these points. These asymptotes are crucial as they dictate the behavior of the function in approaching large positive or negative values. When graphing, careful consideration of these asymptotes helps in sketching the most accurate representation of the function.

Scalar Multiplication

Scalar multiplication involves multiplying a function by a constant, scaling it up or down in the vertical direction. In the case of \(g(x) = 4 \tan x\), the entire tangent function is multiplied by 4, which doesn't affect the period of the function or the location of its vertical asymptotes. This operation is a type of transformation that results in every point on the \(\tan x\) graph being pulled further away from or closer to the x-axis by a factor of 4. Thus, while the zeros and asymptotes remain unchanged, the peaks and valleys of the curve are magnified, giving a steeper, taller curve. This scaling illustrates how modifications can drastically alter the visual dynamics of a function while preserving its fundamental characteristics.