Chapter 4: Problem 29
Find the period, \(x\) -intercepts, and the vertical asymptotes of the given function. Sketch at least one cycle of the graph. $$ y=\tan \pi x $$
Short Answer
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Period: 1; x-intercepts: at multiples of 1; vertical asymptotes: at x = ±0.5, ±1.5, ...
Step by step solution
01
Identify the Period
The period of the tangent function is determined by the coefficient of \(x\) inside the tangent function. For \(y = \tan(\pi x)\), the general form is \(y = \tan(bx)\), where \(b = \pi\). The period of \(\tan(bx)\) is given by \(\frac{\pi}{b}\). Therefore, the period is \(\frac{\pi}{\pi} = 1\).
02
Find the x-Intercepts
Tangent functions have x-intercepts where the function value is zero. This occurs when \(\tan(\pi x) = 0\), which happens at multiples of \(\pi\). Thus, \( \pi x = n \pi\) where \(n\) is an integer. From this, \(x = n\), meaning x-intercepts occur at \(x = 0, \pm 1, \pm 2, ...\).
03
Determine the Vertical Asymptotes
The tangent function has vertical asymptotes where it is undefined. This occurs when \(\tan(\pi x)\) has a vertical asymptote, i.e., where \(\pi x = \frac{(2n+1)\pi}{2}\), leading to \(x = \frac{2n+1}{2}\). Hence, the vertical asymptotes occur at \(x = \pm \frac{1}{2}, \pm \frac{3}{2}, \pm \frac{5}{2}, ...\).
04
Sketch One Cycle of the Graph
To sketch one cycle, note the x-axis at \(x = 0\), the x-intercept. The period of 1 means the cycle repeats every interval of 1 along the x-axis, with asymptotes at \(x = \pm 0.5\). The graph passes through (0,0) and exhibits the asymptotic behavior typical of tangent functions as it approaches the asymptotes at \(x = \pm 0.5\). A full cycle then spans from \(-0.5\) to \(0.5\), repeating along the x-axis.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Tangent Function
The tangent function, denoted as \( y = \tan(x) \), is one of the basic trigonometric functions. It represents the ratio of the sine and cosine functions: \( \tan(x) = \frac{\sin(x)}{\cos(x)} \). The nature of this ratio gives the tangent function its unique properties, such as having a repeating pattern or cycle.
- It is periodic, meaning it repeats its pattern at regular intervals, known as the period.
- It can take any real value, thus it extends infinitely in the positive and negative directions on the y-axis.
- The tangent function has vertical asymptotes, which are points where the function goes to positive or negative infinity.
- It also has multiple x-intercepts, where the graph crosses the x-axis.
Period of a Function
The period of a function refers to the distance over the x-axis after which the function repeats its pattern. For trigonometric functions like the tangent function, this is a fundamental characteristic. The general formula to find the period of the tangent function \( y = \tan(bx) \) is \( \frac{\pi}{b} \), where \( b \) is the coefficient of \( x \) inside the function.In our exercise with \( y = \tan(\pi x) \), the coefficient \( b \) equals \( \pi \). Applying the formula, the period of this function is \( \frac{\pi}{\pi} = 1 \). This indicates that the function repeats its complete cycle as you move along the x-axis every 1 unit. This repeating nature is pivotal as it simplifies analysis of the function, allowing for easier identification of patterns such as x-intercepts and asymptotes.
Vertical Asymptotes
Vertical asymptotes in trigonometric functions are lines where the function approaches infinity. For \( y = \tan(x) \), these asymptotes occur where \( \tan(x) \) is undefined. This happens when the denominator of \( \tan(x) = \frac{\sin(x)}{\cos(x)} \) equals zero, i.e., \( \cos(x) = 0 \).For \( y = \tan(\pi x) \), vertical asymptotes occur at points determined by \( \pi x = \frac{(2n+1)\pi}{2} \), translating to \( x = \frac{2n+1}{2} \).
- The first asymptote lies at \( x = \pm 0.5 \).
- Following asymptotes occur at intervals of 1, such as \( \pm 1.5, \pm 2.5, \ldots \).
X-Intercepts
X-intercepts are the points on the graph where the function crosses the x-axis, meaning the function value is zero at these points. For the tangent function, \( \tan(x) = 0 \) when \( x \) is a multiple of \( \pi \).When working with \( y = \tan(\pi x) \), the x-intercepts are found by solving the equation \( \tan(\pi x) = 0 \). This gives \( \pi x = n\pi \), where \( n \) is an integer. Simplifying, we find that:
- X-intercepts occur at \( x = n \), where \( n = 0, \pm 1, \pm 2, \ldots \).