Skip to main content
Ch. 2 - Graphs of the Trigonometric Functions; Inverse Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Non è quello che usi tu?Cambia libro di testo
Capitolo 2, Problema 36

Graph two periods of the given cosecant or secant function.


y = sec x/2

Guida verificata passo dopo passo
1
Identify the given function: \(y = \sec\left(\frac{x}{2}\right)\). This is a secant function with the argument \(\frac{x}{2}\) inside the secant.
Recall the period of the basic secant function \(y = \sec x\) is \(2\pi\). For \(y = \sec(bx)\), the period is given by \(\frac{2\pi}{|b|}\). Here, \(b = \frac{1}{2}\), so the period is \(\frac{2\pi}{\frac{1}{2}} = 4\pi\).
Since the period is \(4\pi\), two periods will span \(2 \times 4\pi = 8\pi\). So, you will graph the function from \(x = 0\) to \(x = 8\pi\) (or any interval of length \(8\pi\)) to show two full periods.
Identify the vertical asymptotes of \(y = \sec\left(\frac{x}{2}\right)\), which occur where the cosine in the denominator is zero: \(\cos\left(\frac{x}{2}\right) = 0\). Solve for \(x\) to find these asymptotes within the interval of two periods.
Plot key points by evaluating \(y = \sec\left(\frac{x}{2}\right)\) at values where \(\cos\left(\frac{x}{2}\right)\) is \(\pm 1\) (maxima and minima of secant), and sketch the graph between the asymptotes to complete two periods.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
7m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Understanding the Secant Function

The secant function, sec(x), is the reciprocal of the cosine function, defined as sec(x) = 1/cos(x). It is undefined where cosine equals zero, leading to vertical asymptotes in its graph. Recognizing these properties helps in sketching the secant curve accurately.
Video consigliato:
Percorso guidato
6:22
Graphs of Secant and Cosecant Functions

Effect of Horizontal Scaling on Trigonometric Functions

In the function y = sec(x/2), the input to secant is scaled by a factor of 1/2, which stretches the period horizontally. Since the standard period of sec(x) is 2π, dividing x by 2 doubles the period to 4π. This affects how many cycles appear over a given interval.
Video consigliato:
Percorso guidato
6:04
Introduction to Trigonometric Functions

Graphing Periodic Functions with Asymptotes

Graphing secant involves plotting its periodic behavior along with vertical asymptotes where the function is undefined. Identifying these asymptotes, typically where cosine is zero, and marking key points such as maxima and minima, is essential for accurately sketching two full periods.
Video consigliato: