## Wave Function 2002 p1 9b

### kimmy72889

Posted 07 April 2005 - 10:43 AM

From part a i know that sin(x)-cos(x) = (root2)sin(x-pi/4)

i think i know how to get the max and min
max=root2 which occurs when (root2)sin(x-pi/4)=root2
sin(x-pi/4)=1
x-pi/4=pi/2, 5pi/4
x=3pi/4. 3pi/2

is that right? can somebody please tell me how to do the rest of the question and correct me if the max is wrong thank you! x

### Floorball Maniac

Posted 07 April 2005 - 10:57 AM

I haven' t worked it out to see if your right but the method looks right.

You will still have to work out the minimum value (min = - 2)
and where it cuts the x and y axis (x=0, y=0)

Then the fun part... drawing it! OMG I cant draw graphs to save myself!

### aldo

Posted 07 April 2005 - 11:22 AM

Hi, your max turning point is slighly incorrect.

Almost done a complete solution for the question, so will post in a few mins for you.

### aldo

Posted 07 April 2005 - 11:46 AM

I cant find a way to attach the file and post on here, do you want me to e-mail my solution to you?

### Ally

Posted 07 April 2005 - 11:52 AM

QUOTE(aldo @ Apr 7 2005, 12:46 PM)
I cant find a way to attach the file and post on here, do you want me to e-mail my solution to you?

Do you not see a 'File Attachments' bit at the bottom?

### aldo

Posted 07 April 2005 - 11:54 AM

No, I have seen that in the past and attached a file just last night to another topic, but there isn't an attach file at the bottom of the page.

All it has is the post options, enable emotions, signature and all that stuff, and below it post icons which is all the smiley faces.

Then all i can do is add a reply or preview.

### Ally

Posted 07 April 2005 - 12:01 PM

Oh OK... it must not have been enabled for members in this sub-forum. I'm sure George/Steve would be able to sort that out.

### Ally

Posted 07 April 2005 - 12:03 PM

Try posting it to a random thread in the 'Mathematics' forum and I'll see if I can move that post here.

### aldo

Posted 07 April 2005 - 12:05 PM

[attachmentid=56]

Hi, the solution for Q9b from the 2002 Higher is attached, if you have any problems or cant follow it, then let me know.

Sorry had to post as new topic for you, it wouldn't let me attach file in the other topic.

### aldo

Posted 07 April 2005 - 12:08 PM

I have posted in a new topic for you, it is called "Maths Higher - 2002 - Paper I - Q9b."

Let me know if you get it ok.

### Ally

Posted 07 April 2005 - 12:16 PM

Hi, that's it added now.

### kimmy72889

Posted 07 April 2005 - 12:27 PM

thats great, thanks for that!

### George

Posted 07 April 2005 - 12:37 PM

QUOTE(ally @ Apr 7 2005, 01:01 PM)
Oh OK... it must not have been enabled for members in this sub-forum.  I'm sure George/Steve would be able to sort that out.

Yes, that should be it sorted now