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# AQA Core 2 Transformations of Functions question

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1. Hi guys,

I'm revising for the AQA Core 2 exam and came across one I don't understand - I'm not very good at transformations of functions so it might be obvious to you guys.

If you had a graph and you applied the transformation f(x/2) does this just divide each x value by 2 effectively squishing the graph towards the y axis?
Also, if you applied the transformation f(4-x) does this just mean a translation to the right by 4 units?

Blake
2. (Original post by Blake Jones)
Hi guys,

I'm revising for the AQA Core 2 exam and came across one I don't understand - I'm not very good at transformations of functions so it might be obvious to you guys.

If you had a graph and you applied the transformation f(x/2) does this just divide each x value by 2 effectively squishing the graph towards the y axis?
Also, if you applied the transformation f(4-x) does this just mean a translation to the right by 4 units?

Blake
Hi there you replace x with 1/2 x which is a stretch by factor 2 in the x direction.

For the 2nd transformation, you replace x with 4-x so i believe that is saying -x + 4 so therefore you have reflected the graph in the y-axis and translated it to the left by 4 units. Hope this helps, if you got any other questions/issues be sure to check out by core 2 preaparation thread here: http://www.thestudentroom.co.uk/show....php?t=4104433
3. (Original post by Rager6amer)
Hi there you replace x with 1/2 x which is a stretch by factor 2 in the x direction.

For the 2nd transformation, you replace x with 4-x so i believe that is saying -x + 4 so therefore you have reflected the graph in the y-axis and translated it to the left by 4 units. Hope this helps, if you got any other questions/issues be sure to check out by core 2 preaparation thread here: http://www.thestudentroom.co.uk/show....php?t=4104433
Ah, awesome, thank you
4. (Original post by Blake Jones)
Ah, awesome, thank you
No problem, does what i said make sense? I was really intimidated by these types of questions until i really got my head around them so be sure to ask if you still don't understand why the answer is what it is
5. (Original post by Rager6amer)
For the 2nd transformation, you replace x with 4-x so i believe that is saying -x + 4 so therefore you have reflected the graph in the y-axis and translated it to the left by 4 units.
This is not correct.

Reflection in the y-axis would give you f(-x)

Then if you were to translate that to the left by 4 you would get f(-(x+4)) = f(-4-x)

Instead write f(4 - x) as f(-(x - 4)) so this is a refelection in the y-axis followed by a translation 4 to the right.
6. (Original post by notnek)
This is not correct.

Reflection in the y-axis would give you f(-x)

Then if you were to translate that to the left by 4 you would get f(-(x+4)) = f(-4-x)

Instead write f(4 - x) as f(-(x - 4)) so this is a refelection in the y-axis followed by a translation 4 to the right.
Oh, okay, I think I get that, thanks.
7. (Original post by notnek)
This is not correct.

Reflection in the y-axis would give you f(-x)

Then if you were to translate that to the left by 4 you would get f(-(x+4)) = f(-4-x)

Instead write f(4 - x) as f(-(x - 4)) so this is a refelection in the y-axis followed by a translation 4 to the right.
woops you are right haha sorry idk how i missed that :P
8. (Original post by Rager6amer)
woops you are right haha sorry idk how i missed that :P
Thanks anyhow, your suggestion was still better than mine!!
9. (Original post by Blake Jones)
Thanks anyhow, your suggestion was still better than mine!!
Well at least i showed why you cant rush transformations though, right? Lol :P
10. (Original post by Rager6amer)
Well at least i showed why you cant rush transformations though, right? Lol :P
Indeed you did! Haha!

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