Graphing Sine Function
The trigonometric ratios can also be considered as functions of a variable which is the measure of an angle. This angle measure can either be given in degrees or radians . Here, we will use radians.
The graph of a sine function y = sin x is looks like this:
Properties of the Sine Function, y = sin x.
Range: [–1, 1] or 
y -intercept: (0, 1)
x -intercept: 
, where n is an integer.
Period: 
Continuity: continuous on 
Symmetry: origin (odd function)
The maximum value of y = sin x occurs when 
, where n is an integer.
The minimum value of y = sin x occurs when 
, where n is an integer.
Amplitude and Period of a Since Function
The amplitude of the graph of y = a sin bx is the amount by which it varies above and below the x -axis.
Amplitude = | a |
The period of a sine function is the length of the shortest interval on the x -axis over which the graph repeats.
Period = 
Example :
Sketch the graphs of y = sin x and y = 2 sin x . Compare the graphs.
For the function y = 2 sin x , the graph has an amplitude 2. Since b = 1, the graph has a period of .
Thus, it cycles once from 0 to with one maximum of 2, and one minimum of –2.
Observe the graphs of y = sin x and y = 2 sin x . Each has the same x -intercepts, but y = 2 sin x has an amplitude that is twice the amplitude of y = sin x .
Also see Trigonometric Functions.
