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# How to sketch f(|x|) ?? watch

1. There's a question about this on the january 2008 paper....and the mark scheme suggest something utterly different.

I thought is y= f(x) then y =f(|x|) would mean drawing the part of the curve in the positive x axis and the reflecting it on the negative x axis ....

Is this not the case.??? I'm very confused indeed.
2. you reflect it in the y axis.
4. its clearly given in the C3 book for drawing y=f(|x|) u reflect all wat is drawn on the right side to the left side,with y axis as the mirror line...
5. (Original post by face05)
There's a question about this on the january 2008 paper....and the mark scheme suggest something utterly different.

I thought is y= f(x) then y =f(|x|) would mean drawing the part of the curve in the positive x axis and the reflecting it on the negative x axis ....

Is this not the case.??? I'm very confused indeed.
To sketch y =f(|x|) draw y=f(x) for x>0, then reflect in the y-axis.
6. (Original post by face05)
It's okay calm down.
How about checking your C3 book ? You'll find many examples there.
7. does evryone here has a C3 exam tomorrow
if so are the timings same in the west as in the east????just askin'
8. Think about it. If you have and (where a is positive, so -a is negative, i.e. x is negative) then . So, , for example. This means that if you have then it is unchanged if a is positive, so for all , the graph of is identical to the graph of . However, when , you'll notice that , and hence and so on, so all you do is reflect what you've just drawn in the y-axis.
9. (Original post by nuodai)
Think about it. If you have and (where a is positive, so -a is negative, i.e. x is negative) then . So, , for example. This means that if you have then it is unchanged if a is positive, so for all , the graph of is identical to the graph of . However, when , you'll notice that , and hence and so on, so all you do is reflect what you've just drawn in the y-axis.
How about y= |f(x)| ? How'd you explain what we sketch?
10. (Original post by FZka)
How about y= |f(x)| ? How'd you explain what we sketch?
Lol I'm nt pancing or anything ...its just that I keep seeing different ways of doing it. The book does it the way I said it (in the first post)

First I thought is just like doing Y= |f(x)| but this affect the y co ordinates y= f(|x|) affect the x co cordinates...

The mark scheme seem to be doing it differently.... so does the book and the are not identical. That's why I thought an example would be best understood

If you've got the hiennman book just give me a page refrence or check pg 57 example 7 yourself and you know what I mean.
11. (Original post by FZka)
How about y= |f(x)| ? How'd you explain what we sketch?
whenever y<0 reflect it on the x-axis so there is no negative y
12. Reflect everything in the right hand side to the left hand side of the graph. (Reflect in y axis)

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