1. T5.1b To Graph the Cosine Curve Do not say the answers out loud!!!
T5.1b To Graph the Cosine Curve
Do not say the answers out loud!!!
1. Put up your dukes.
2. Living off the land.
3. Pleading the fifth.
4. Backhand slice.

2. OPENER: Together, as a group, determine the equation of this graph:
y = -4 sin(x)

3. Active Learning Assignment?
“0”
Max
“0”
Min
“0”

4. * LESSON: Standard form for Cosine Function: y = a*cos b * (x – h) + k
Let’s look at the cosine curve on a Gizmo: *

5. Cosine: More Patterns, Patterns, Patterns!
The HORIZONTAL pattern has:
beginning, ¼, ½, ¾, and end marks. (same as sine).
One normal period, horizontally, is: 0, π/2, π, 3π/2, 2π.
(same as sine, and will also change.)
Graph y = cos(x)
beginning
end

6. * The positive VERTICAL pattern has:
max, “0”, min, “0”, max (“0” is the middle.)
The normal max is 1 and the normal min is -1
(different from sine) *
Graph y = cos(x)
max 1
“0”
min -1
Max
“0”
Min
“0”
Max
Always write both the x and y coordinates!!!

7. Graph y = cos(x)
Max
“0”
Min
“0”
Max

8. What happens when we multiply the sine function by a number?
y = cos(x)
vs. y = 2cos(x)
This change is called the amplitude.
The equation is y = a cos(x)

9. Graph y = 5cos(x)
Max
“0”
Min
“0”
Max

10. Graph y = –1/5 cos(x)
Min
“0”
Max
“0”
Min

11. Active Learning Assignment:
Graph I: 1, 4, 5, 8
Writing: Compare and contrast the sine and cosine curves Find at least two ways that they are alike, and two ways that they are different.