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Trig graph problem

  • Thread starter özge
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  • #1
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Please Help,urgent

i have a trigonometry question and i really dont know how to solve i checked couple of books but still no hope here it is:

im supposed to draw the graph of y=cos¶/3(x-1) but i couldnt

so please help..
 

Answers and Replies

  • #2
Tom Mattson
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Your equation is showing up funny on my browser.

Is it supposed to be this:

[tex]
y=cos(3x-1)
[/tex]

or this:

[tex]
y=cos(\frac{1}{3x-1})
[/tex]

?
 
  • #3
arildno
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özge said:
i have a trigonometry question and i really dont know how to solve i checked couple of books but still no hope here it is:

im supposed to draw the graph of y=cos¶/3(x-1) but i couldnt

so please help..
y=cos¶/3(x-1)???????????????????????????????????????????????????
Neither can I. Please type in the CORRECT formula.
 
  • #4
Lisa!
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Tom Mattson said:
Your equation is showing up funny on my browser.

Is it supposed to be this:

[tex]
y=cos(3x-1)
[/tex]

or this:

[tex]
y=cos(\frac{1}{3x-1})
[/tex]

?
I think it's something else!
 
  • #5
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y=cos pi/3(x-1)

now ok?
 
  • #6
arildno
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Ok, so it is:
[tex]y=\cos(\frac{\pi}{3x-1})[/tex]

Hints:
1. Find the point of singularity, where y is not defined.
2. Determine the set of points were y is -1, 0, 1 respectively.
In particular, see what this implies for the function's behaviour very close to the singularity found in 1.
 
  • #7
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ok it is not that y is equal to cos multiplied by pi/3 multiplied by (x-1)
 
  • #8
Tom Mattson
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Still not OK, and I suspect that it's because you aren't placing your parentheses properly.

What you have written is this:

[tex]y=cos(\frac{\pi}{3x-1})[/tex].

Now that's a perfectly legitimate function, but I strongly suspect that it is not the one you are supposed to graph, simply because it's too difficult for a trigonometry course. I am inclined to think that you really meant this:

[tex]y=cos[\frac{\pi}{3}(x-1)][/tex].

Am I right?
 
  • #9
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(x-1) isnt near 3
 
  • #10
Tom Mattson
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I don't know what that means.
 
  • #11
arildno
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özge:
If Tom Mattson is right, here's how you could have written this properly:
y=cos(pi*(x-1)/3)
 
  • #12
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Tom Mattson said:
Still not OK, and I suspect that it's because you aren't placing your parentheses properly.

What you have written is this:

[tex]y=cos(\frac{\pi}{3x-1})[/tex].

Now that's a perfectly legitimate function, but I strongly suspect that it is not the one you are supposed to graph, simply because it's too difficult for a trigonometry course. I am inclined to think that you really meant this:

[tex]y=cos[\frac{\pi}{3}(x-1)][/tex].

Am I right?
u are right
 
  • #13
Tom Mattson
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özge said:
ok it is not that y is equal to cos multiplied by pi/3 multiplied by (x-1)
This can't be right. cos without an argument makes no sense.
 
  • #14
arildno
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özge said:
ok it is not that y is equal to cos multiplied by pi/3 multiplied by (x-1)
Do you know what the cosine function is??
What is its argument?
 
  • #15
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what u wrote :[tex]y=cos[\frac{\pi}{3}(x-1)][/tex]
was right im sorry im new to these things and i diddnt know how to write
 
  • #16
Tom Mattson
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özge said:
u are right
Alrighty then!

Here are a couple of tips to get you started.

*Examine the graph of [itex]y=cos(x)[/itex].

*Note that if you have the graph of some function [itex]y=f(x)[/itex] then you can obtain the graph of [itex]y=f(x+a)[/itex] by shifting the graph of [itex]y=f(x)[/itex] horizontally by [itex]a[/itex] units. You move to the right if [itex]a<0[/itex] and to the left if [itex]a>0[/itex].

*The period [itex]T[/itex] of a cosine function [itex]y=A\cos[k(x+a)][/itex] is [itex]T=\frac{2\pi}{k}[/itex].

Give it a shot and see how you do, OK?
 
  • #17
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ok, thanks
 

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