# Functions - reflection - Core 3 EdexcelWatch

#1
Hello,

I'm wondering if anyone has a technique to reflect an inverse or a function in the line y=x. I can't imagine how a specific graph or a limited function would look like in the line y=x without physically having to place a mirror on the line. If I am not mistaken, I believe we can't use a mirror in the exam hosted by Edexcel? How do I get around this...? One may suggest 'just flip the co-ordinates'', I.e. (4,18) being f(x) and f^-1(x) being (18,4), suppose you can't do this for a specific function, what do I do then - help please?
0
4 years ago
#2
(Original post by Cool-Light)
Hello,

I'm wondering if anyone has a technique to reflect an inverse or a function in the line y=x. I can't imagine how a specific graph or a limited function would look like in the line y=x without physically having to place a mirror on the line. If I am not mistaken, I believe we can't use a mirror in the exam hosted by Edexcel? How do I get around this...? One may suggest 'just flip the co-ordinates'', I.e. (4,18) being f(x) and f^-1(x) being (18,4), suppose you can't do this for a specific function, what do I do then - help please?

The probability of having to actually perform an actual reflection in an exam is around 5%!

The typical marking scheme allocation for reasonably correct shape is 1 mark!

Learn and have understanding for the mathematically important parts otherwise you will have grey hair (or no hair) and ulcers before you are 20.
0
#3
(Original post by TeeEm)
The probability of having to actually perform an actual reflection in an exam is around 5%!

The typical marking scheme allocation for reasonably correct shape is 1 mark!

Learn and have understanding for the mathematically important parts otherwise you will have grey hair (or no hair) and ulcers before you are 20.
Shnap, you must know me in real life or something LOL. And okay thanks for the statistics. I'm running out of hair as we speak - what's the solution?
0
#4
(Original post by TeeEm)
The probability of having to actually perform an actual reflection in an exam is around 5%!

The typical marking scheme allocation for reasonably correct shape is 1 mark!

Learn and have understanding for the mathematically important parts otherwise you will have grey hair (or no hair) and ulcers before you are 20.
Thanks for the re-assurance aswell... Grey hair and ulcer before i'm 20..
0
4 years ago
#5
(Original post by Cool-Light)
Shnap, you must know me in real life or something LOL. And okay thanks for the statistics. I'm running out of hair as we speak - what's the solution?
Isn't it obvious?

Do not worry as it is unlikely to affect your grade as I just explained.

Draw the line y=x (dotted) in the picture to indicate your intention.
Or draw the graph close to the end of the page so you can fold the page gently so you can see roughly where the image would lie.
0
4 years ago
#6
(Original post by Cool-Light)
Hello,

I'm wondering if anyone has a technique to reflect an inverse or a function in the line y=x. I can't imagine how a specific graph or a limited function would look like in the line y=x without physically having to place a mirror on the line. If I am not mistaken, I believe we can't use a mirror in the exam hosted by Edexcel? How do I get around this...? One may suggest 'just flip the co-ordinates'', I.e. (4,18) being f(x) and f^-1(x) being (18,4), suppose you can't do this for a specific function, what do I do then - help please?
If you had to draw a function flipped along the y-axis would you be able to?

Well drawing a function flipped along the y=x axis is simple, you first rotate the page 90 degrees (so the x-axis is pointing upwards) and sketch the function, now draw a new function that is a reflection of your sketched function about the x-axis.
0
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