The Student Room Group

Good ways to remember graph transformations?

Hello you fine people of TSR,

Basically i wondered if you have found a way of remembering graph transformations. The understanding of how they work has alway eluded me so havving to learn them. I forget which way the curve goe and don't get me started with sketching the modulus of graphs.

the ones i'm talking about are

y= f(x) + A (move A units up)
y= f(x-A) (move A units right)
y= -f(x) reflection in x axis
y= f(-x) reflection in y axis
y= Af(x) stretch parrallel to the y axis with scale factor A
y= f(ax) stretch parrallel to the x axis with scale factor 1/A
And both modulus functions.

Yes i know you can tell me off for being lazy but if anybodys got any little dittys/sayings/songs/ballads/haiku/rhymes of how to remember which wahy to translate the curve it would be most kind of you.

Cheers
I don't understand why you can't just spend half an hour working out why they work the way they do. Then you'll never have to 'learn' anything. You'll just know it.
Reply 2
Inside the Brackets does x with opposite sign, outside does y.

*a is stretch
+a is translate
- is reflect
|x| is put it all on the positive side.

But basically, as above, figure out why it is, learning it takes longer than understanding it.
Reply 3
Honestly i've tried going over it a fair few times... Its just one of these things my brain likes take in and then muddles around with while its in there causing me to mess up. The exams not for a while so of course i'll be attempting to learn them but i was just wondering if anybody had a way of remembering them that worked for them.
Reply 4
mullac14
Hello you fine people of TSR,

the ones i'm talking about are

y= f(x) + A (move A units right)
y= f(x-A) (move A units up)
y= -f(x) reflection in y axis
y= f(-x) reflection in x axis
y= Af(x) stretch parrallel to the y axis with scale factor A
y= f(ax) stretch parrallel to the x axis with scale factor 1/A
y=f(lXl) reflect all parts of the curve to the right of the y-axis
y= lf(x)l reflect the line in the x axis

Cheers



y= f(x) + A (move A units right)
No. Move A units upwards.

y= f(x-A) (move A units up)
No. Move A units right.

y= -f(x) reflection in y axis
Reflect in x axis.

y= f(-x) reflection in x axis
Reflect in Y axis

y= Af(x) stretch parrallel to the y axis with scale factor A
correct!

y= f(ax) stretch parrallel to the x axis with scale factor 1/A
Correct!

y=f(lXl) reflect all parts of the curve to the right of the y-axis
generalebriety
.

This means mirror everything in the second and forth quadrant with the first and third quadrant doesn't it?

y= lf(x)l reflect the line in the x axis
No. This means there can be no negative Y co-ordinate. So make them the corresponding positive values.
Reply 5
Tallon
...


wow i was even copying that out of a book and i messed it up... I'm not having a good day apparantly!

Anyway thanks for the corrections.
Reply 6
oo what you can do is:for f(-x), you say that because it is making all the x values negative, therefore y-axis acts as a mirrorfor -f(x), all the y values change, so x-axis becomes a mirror[Sorry for replying after a very long time lol]
Reply 7
Original post by mullac14
Hello you fine people of TSR,

Basically i wondered if you have found a way of remembering graph transformations. The understanding of how they work has alway eluded me so havving to learn them. I forget which way the curve goe and don't get me started with sketching the modulus of graphs.

the ones i'm talking about are

y= f(x) + A (move A units up)
y= f(x-A) (move A units right)
y= -f(x) reflection in x axis
y= f(-x) reflection in y axis
y= Af(x) stretch parrallel to the y axis with scale factor A
y= f(ax) stretch parrallel to the x axis with scale factor 1/A
And both modulus functions.

Yes i know you can tell me off for being lazy but if anybodys got any little dittys/sayings/songs/ballads/haiku/rhymes of how to remember which wahy to translate the curve it would be most kind of you.

Cheers


crazy to think that ur a fully grown adult now. 13 years is mad

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