In the last post, we talk about single transformation of graphs. This could mean a single reflection, translation or scaling. However, in the A Level exam, we are going to do multiple transformations.
Order of transformation
Whenever we are doing multiple transformation, it is recommended to follow this order:
- Translate in x direction (Tx)
- Scale/ reflect in x- direction (Sx)
- Scale/ reflect in y- direction (Sy)
- Translate in y direction (Ty)
Often, we abbreviate this order to Tx, Sx, Sy, Ty.
Example of multiple transformation
Given y = f(x), describe the series of transformation needed to obtain y = 2f(3x+2)-5.
Solutions:
To sketch y = 2f(3x+2)-5, we should transform the graph of y = f(x) in this order:
Step 1: translate y = f(x) by -2 units in the x- direction to obtain y = f(x+2)
Step 2: Scale y= f(x+2) by a scale factor of 1/3 parallel to the x-axis to obtain y = f(3x+2)
Step 3: Scale y = f(3x+2) by a scale factor of 2 parallel to the y- axis to obtain y = 2f(3x+2)
Step 4: Translate y= 2f(3x+2) by -5 units in the y direction to obtain y = 2f(3x+2)-5