Cosecant Function

Definition

Definition of the Cosecant Function

In a right triangle, let θ\theta be an acute angle, then cosecant is defined as:

cscθ=hypotenuseopposite\csc \theta = \frac{\text{hypotenuse}}{\text{opposite}}

where “hypotenuse” is the longest side of the triangle, and “opposite” refers to the side opposite to angle θ\theta.

符号说明
SymbolTypePronunciation/ExplanationMeaning in This Definition
θ\thetaGreek letterTheta (theta)Represents the measure of an angle (acute angle)

Properties

  • Domain: xkπx \neq k\pi
  • Range: (,1][1,+)(-\infty, -1] \cup [1, +\infty)
  • Period: 2π2\pi
  • Parity: Odd function
  • Monotonicity: Increasing or decreasing in each monotonic interval
  • Symmetry: Symmetric about the origin

Graph

Exercises

Exercise1

Find the domain and range of y=cscxy = \csc x.

Answer and Explanation(3 个标签)
cosecant functiondomainrange

Domain: xkπx \neq k\pi; Range: (,1][1,+)(-\infty, -1] \cup [1, +\infty).

Exercise2

Determine the periodicity and parity of y=cscxy = \csc x.

Answer and Explanation(3 个标签)
cosecant functionperiodparity

Period is 2π2\pi, it is an odd function.

Summary

Symbols Appearing in This Article

SymbolTypePronunciation/ExplanationMeaning in This Article
π\piGreek letterPi (pie)Pi, used to represent the period of the cosecant function (2π2\pi)

Bilingual Glossary

Chinese TermEnglish TermPhoneticExplanation
余割函数cosecant function/kəʊˈsiːkənt ˈfʌŋkʃən/One of the trigonometric functions, denoted as cscx\csc x
余割cosecant/kəʊˈsiːkənt/Function name, abbreviated as csc\csc
周期period/ˈpɪəriəd/The smallest interval at which function values repeat
定义域domain/dəʊˈmeɪn/The range of values for the independent variable