13.4 201516 Graphing sin and cos.notebook March 09, 2016
Today's TargetI Can...
... graph sin and cos functions
Alg 1
YOTL: 6 graphs
13.4 & 5
13.4 201516 Graphing sin and cos.notebook March 09, 2016
Amplitude and Period of Sine and
Cosine
y = AsinBx
y = AcosBx
amplitude: A
period: 2π/B
STEPS WHEN GRAPHING:
1. Identify " sin" or "cos" ?
2. Mark out the amplitude: using |A|....plot on y-axis
3. Mark the period using P = 2π |B|
4. Mark 1/4, 1/2, 3/4 of the period.... use 1/2, 1/2, and sum...
5. Sketch
13.4 201516 Graphing sin and cos.notebook March 09, 2016
1. y = 4cos2θ
2. y = 3sin½θ
3. y = 5sin2π/7θ
4. y = 2sinθ
5. y = 6cos2π/3θ
EXAMPLES
1. y = 4cos2θ
13.4 201516 Graphing sin and cos.notebook March 09, 2016
Deduction:
a. whole # in front of θ⇒
b. fraction in front of θ⇒
c. π statement in front of θ⇒
d. negative in front of statement⇒
see animation
colorful sin
colorful tan
sin, cos, tan...animationswith amp.
13.4 201516 Graphing sin and cos.notebook March 09, 2016
Writing an Equation of sin or cos
y = A sin BΘy = A cos BΘ
1. Is it sin or cos?2. Find amplitude of curve3. Find period of curve4. Make "A" negative if x symmetry is shown5. Use P = 2π
B1. Find amplitude of curve2. Find period of curve3. Make "A" negative if x symmetry is shown4. Use P = 2π
B
Write an equation for each of the following:1. Is it sin or cos?2. Find amplitude of curve3.. Find period of curve4. Make "A" negative if x symmetry is shown5. Use P = 2π
B
y = A sin BΘy = A cos BΘ
13.4 201516 Graphing sin and cos.notebook March 09, 2016
y = 4sinθ
y = A sin BΘy = A cos BΘEx. 1 write the eqn
1. Is it sin or cos?2. Find amplitude of curve3.. Find period of curve4. Make "A" negative if x symmetry is shown5. Use P = 2π
B
13.4 201516 Graphing sin and cos.notebook March 09, 2016
Write an equation for each graph:
1. amplitude: 2 period: π
2. amplitude: 3 period: 2π
3. amplitude: 1.5 period: π/2
Page 739172128,29
Page 7475,6,10,13,22,23
13.4 201516 Graphing sin and cos.notebook March 09, 2016
13.7 Translating Graphs
y = sinθ + 3 means: move the graph up 3 steps
y = sin(Θ π/2)
means: move the graph π/2 units to the right (opposite of what is in the ( )
13.4 201516 Graphing sin and cos.notebook March 09, 2016
tell what happens to each....ps = phase shift and graph it and vs = vertical shift
1. y = cos (Θ - π/2) + 2