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Question: Describe a transformation that maps the graph of y=2^x onto y=2^(x-1). The answer is apparently a stretch in the y direction, scale factor 1/2 but I don't understand how to get to that answer. Thanks for your help.

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Hi Jordan,
In this case there are two ways to compare the graphs of y = 2^x and y = 2^(x-1)

Looking at the exponents, the graph of y = 2^(x-1) is simply the graph of y = 2^x moved horizontally to the right (along the x-axis) by 1 unit.

Algebraically, y = 2^(x-1) = (2^x)(2^-1) = (2^x)(1/2)
and we can see that the graph of y = 2^(x-1) is a stretch of y = 2^x in the y direction by a scale factor of 1/2.


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Ahmed Salami


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