Page 43 - Ebook Trigonometri_Krisna Hasugian_MESP 2019
P. 43
UNDERSTAND KEY FEATURES OF GRAPHS OF TRIG FUNCTIONS
In this section you will get a brief introduction to the graphs of the three main trig
functions, sine, cosine, and tangent. This section will not go over how to actually
graph these functions, but will go over how to identify key features of the graphs
of each function.
The graphs of sine and cosine are considered periodic functions, which basically
means their values repeat in regular intervals known as periods.
A periodic function is a function f such that
( ) = ( + )
We talked about the fact that one revolution of the unit circle is 2π radians, which
means that the circumference of the unit circle is 2π. Therefore, the sine and
cosine function have a period of 2π.
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