Skip to main content
Ch. 2 - Graphs of the Trigonometric Functions; Inverse Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Not the one you use?Change textbook
Chapter 2, Problem 28

Use each graph to obtain the graph of the corresponding reciprocal function, cosecant or secant. Give the equation of the function for the graph that you obtain.


<IMAGE>

Verified step by step guidance
1
Identify the original trigonometric function from the given graph, which will be either sine or cosine, since their reciprocals are cosecant and secant respectively.
Recall that the reciprocal function of sine is cosecant, defined as \(y = \csc x = \frac{1}{\sin x}\), and the reciprocal function of cosine is secant, defined as \(y = \sec x = \frac{1}{\cos x}\).
Note the key features of the original graph: where the function crosses the x-axis (zeros), where it has maximum and minimum values, and its period. These features help determine the behavior of the reciprocal function.
Use the fact that the reciprocal function will have vertical asymptotes where the original function is zero, because division by zero is undefined. For example, if the original function is \(\sin x\), then \(\csc x\) has vertical asymptotes where \(\sin x = 0\).
Sketch the reciprocal graph by plotting points where the original function has maximum and minimum values (these become the minimum and maximum points of the reciprocal), and draw vertical asymptotes at the zeros of the original function. Finally, write the equation of the reciprocal function based on the original function identified.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
5m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Reciprocal Trigonometric Functions

Reciprocal functions like cosecant (csc) and secant (sec) are defined as the reciprocals of sine and cosine, respectively. Specifically, csc(x) = 1/sin(x) and sec(x) = 1/cos(x). Understanding these relationships is essential to transform sine or cosine graphs into their reciprocal counterparts.
Recommended video:
6:04
Introduction to Trigonometric Functions

Graphing Reciprocal Functions

To graph reciprocal functions, identify points where the original sine or cosine function is zero, as these correspond to vertical asymptotes in the reciprocal graph. The reciprocal graph will have peaks where the original function has maxima or minima, and it will never cross the x-axis since the reciprocal of zero is undefined.
Recommended video:
6:22
Graphs of Secant and Cosecant Functions

Equation Identification from Graphs

Determining the equation from a graph involves recognizing amplitude, period, phase shift, and vertical shift. For reciprocal functions, these parameters come from the original sine or cosine function before taking the reciprocal. Accurately identifying these features allows writing the correct cosecant or secant function equation.
Recommended video:
6:50
Convert Equations from Polar to Rectangular