Worked solution
Account for order in two vertical transformations
State a sequence of transformations which transforms the graph of to the graph of .
CJC · Transformations · Example 9
Method 1: scale, then translate
Answer
Scale parallel to the y-axis by factor 2, then translate 1 unit in the positive y-direction.
The Teacher emphasises y replaced by , followed by y replaced by . The source recommends scaling before translation for vertical changes.
Double output distances
Replace y by and solve for y.
Translate up one unit
Apply the y-replacement to the current equation.
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Method 2: translate, then scale
Answer
Translate unit in the positive y-direction, then scale parallel to the y-axis by factor 2.
The Teacher emphasises y replaced by , followed by y replaced by . The later scaling also doubles the earlier translation.
Translate up one half
Use the smaller translation before doubling.
Double all outputs
The constant term is doubled as well.
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