Trig Functions and Graphs Flashcards
Vertical dilation of y=f(x)
y=kf(x) - scale factor k
If k>0
the function is stretched vertically
If 0
the function is compressed vertically
If k = -1
the function is reflected in the x-axis
What is the amplitude
the height from the centre of the periodic function to the maximum or minimum value
What is a horizontal dilation of y = f(x)
y=f(ax) - scale factor 1/a
If a > 0
the function is stretched
If 0<a></a>
the function is compressed
If a = -1
the function is reflected in the y-axis
What is a period
The length of one cycle of a periodic function on the x-axis
Period of cosx and sinx
Given y=sin(ax),
2 π/a
Period of tanx
Given y=tan(ax)
π/a
Vertical translation of y=f(x)
y=f(x) +c
If c>0
centre is translated up
If c<0
centre is translated down
Horizontal translation =
phase shift
What is the phase of y=sin/cos/tan
b:
y=sin(x+b)
y=cos(x+b)
y=tan(x+b)
If b > 0
the phase shift is to the left
If b<0
the phase shift is to the right
What is a phase
angle where x=0 (let x =0 to find phase)
What order to apply transformations in
Start with standard base function (y=sin/cos/tanx)
- Dilations
- Translations
How to solve trig equations graphically
Treat each side of function as a separate function
graph each function separately
solution - x-value where the graphs intersect
How to solve trig equations algebraically
Find the new domain (e.g 2x –> domain=0<2x<720)
Use all stations to central to find all angles in new domain
Find values of x
How to solve trig equations algebraically with a phase shift
Find the new domain by using an inequality with (x+phase) in the centre
Then solve the same way and solve for x, ensuring all angles are in the new domain