Graphs of Sine and Cosine

Cosine Graph

Parent Function Graph y=cosx
The Graph of Cosine shows the cosine value for different radian measurements on the Unit Circle. The beginning and end of a cosine graph is at the maximum y-value.  The graph reaches the minimum y-value at the half-way point.  This graph shows that at a value of 0 radians the cosine value of that angle on the unit circle is 1, at 1/2π radians the cosine function of that angle is 0 on the unit circle, etc.


A= Amplitude (Vertical Stretch or Shrink)
B= Horizontal Stretch or Shrink
C= Horizontal Shift
D= Vertical Shift

Steps for Graphing the Cosine Function:
1. Always start with D to determine the sinusoidal axis
    -In the graph above, D=0, therefore the sinusoidal axis is at 0 on the y-axis
2. Determine the Amplitude
    -Plot the maximum and minimum y values of your graph
    -In this graph, the amplitude is 1 because A=1
3. Determine the period
    -To find the period use the equation 2π/B
    -The period here is 2π because B=1
    -The graph above is graphed
5. Label Axis
    -Y-axis and X-axis