Given vertical translation a (+ to shift up, - to shift down), vertical scaling b (larger to grow, smaller to shrink), horizontal translation c (+ to shift right, - to shift left), and horizontal scaling d (larger to grow, smaller to shrink), the function transformation would be:
(f((x-c)/d)+a)/b
You can pick and choose values. If you don't have a or c, replace with 0. If you don't have b or d, replace with 1.
Assume our function f was the sine function. sin(x):
Say we wanted to shift the whole function to the right by +1, i.e. up the x-axis. c=1 and our transformation would be sin(x - [+1]):
Note how the graph used to cross the x-axis at 0 (red), but now crosses it at 1 (green).
Say we now wanted to stretch it longer, i.e. horizontally scale it. Maybe stretch it twice as long. If we choose a horizontal scaling factor of d=2, our new function would be sin((x-1)/2):
Now perhaps we want to shift it upwards, e.g. a=1. Our new function is sin((x-1)/2)+1:
And finally, we want to stretch our function in the vertical axis, perhaps also by double, so b=2. (sin((x-1)/2)+1)*2:
Before, it ranged from a minimum y of 0 to a maximum y of 2, now the maximum y is 4.
2 comments:
I'm going to be nitpicky on your last two formulas of sin(x). To shift it upwards, the function should be sin((x-1)/2)+1.
Meaning a should be applied after the sin function. Same with your last equation. It should be (sin((x-1)/2)+1)*2
:)
No, that's not nitpicky, that's a typo on my part. :) I had it correct in the top formula, just not the application. Thanks for the correction!
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