Skip to main content
Ch. 4 - Graphs of the Circular Functions
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161당신이 사용하는 게 아니라요?교과서 변경
5장, 문제 19

Graph each function over a one-period interval.
y = cot (3x)

검증된 단계별 안내
1
Identify the period of the function \(y = \cot(3x)\). Recall that the period of \(\cot(kx)\) is given by \(\frac{\pi}{k}\). Here, \(k = 3\), so the period is \(\frac{\pi}{3}\).
Choose a one-period interval to graph the function. Since the period is \(\frac{\pi}{3}\), a convenient interval is from \(0\) to \(\frac{\pi}{3}\).
Determine the key points within the interval where the function is undefined or crosses the x-axis. For \(\cot(3x)\), vertical asymptotes occur where \(\sin(3x) = 0\), i.e., at \(3x = n\pi\) for integers \(n\). Within \(0 \leq x \leq \frac{\pi}{3}\), this happens at \(x=0\) and \(x=\frac{\pi}{3}\).
Find the zeros of the function where \(\cot(3x) = 0\). This occurs when \(\tan(3x)\) is undefined, or equivalently when \(3x = \frac{\pi}{2} + n\pi\). Within the interval, this is at \(x = \frac{\pi}{6}\).
Plot the vertical asymptotes at \(x=0\) and \(x=\frac{\pi}{3}\), the zero at \(x=\frac{\pi}{6}\), and sketch the curve of \(y = \cot(3x)\) between these points, noting that \(\cot(3x)\) decreases from \(+\infty\) to \(-\infty\) over one period.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
도움이 되었나요?

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Period of Trigonometric Functions

The period of a trigonometric function is the length of the interval over which the function completes one full cycle. For cotangent, the basic period is π, but when the function is y = cot(kx), the period becomes π divided by the absolute value of k. Understanding this helps determine the interval over which to graph the function.
추천 영상:
5:33
Period of Sine and Cosine Functions

Cotangent Function Properties

The cotangent function, cot(x), is the reciprocal of the tangent function and has vertical asymptotes where sine is zero. It decreases from positive infinity to negative infinity within each period. Recognizing its shape and asymptotes is essential for accurate graphing.
추천 영상:
5:37
Introduction to Cotangent Graph

Effect of Horizontal Scaling on Graphs

Multiplying the variable x by a constant k inside a function, as in cot(3x), horizontally compresses or stretches the graph. Specifically, the graph compresses by a factor of 1/k, reducing the period and increasing the frequency of cycles within a given interval.
추천 영상:
5:10
Introduction to Graphs & the Coordinate System