Secant, Cosecant and Tangent

In this lesson we will look at the trigonometric functions: secant, cosecant and tangent.

We can get three more trigonometric functions by taking the reciprocals of three basic functions: sine, cosine and tangent.

The secant function is the reciprocal of the cosine function. The abbreviation of secant is sec.

The cosecant function is the reciprocal of the sine function. The abbreviation of cosecant is csc or cosec.

The cotangent function is the reciprocal of the tangent function. The abbreviation of cotangent is cot.

Example:
Given that , and that θ is acute, find, without using a calculator, the value of
a)  sec θ
b) cot θ

Solution:

Theta is in the first quadrant.
We can use Pythagoras theorem to get the third side.

a) We then get that

b) We have

Videos

An introduction to the trigonometric functions - sin, cos, tan, csc, sec, cot
Professor Edward Burger introduces the trigonometric functions.

Opposite Sides, Adjacent Sides and Hypotenuse of a Right Triangle.
Definition of Cos, Sin, Tan, Csc, Sec, Cot

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