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Finding the domain and range without a calculator

  • Thread starter Burjam
  • Start date
  • #1
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1

Homework Statement



Find the domain and range of the following function without the use of a calculator:

f(x) = sec (pi x/4)

Homework Equations



As far as I know, this problem doesn't specifically require "equations". Therefore I am leaving this section blank. Not because I am a malicious poster that is trying to break the rules and upset the administration here, but simply because I don't know any equations for this problem.

The Attempt at a Solution



I tried flipping this and finding the cosine of 4pi and graphing it. But I failed to come up with a valid graph and was puzzled. I could take a picture of my "graph", but I don't think anyone could read it. Help would be greatly appreciated here.
 

Answers and Replies

  • #2
3,812
92
For what values of x, sec(x) is not defined?
 
  • #3
SammyS
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Homework Helper
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Homework Statement



Find the domain and range of the following function without the use of a calculator:

f(x) = sec (pi x/4)

Homework Equations



As far as I know, this problem doesn't specifically require "equations". Therefore I am leaving this section blank. Not because I am a malicious poster that is trying to break the rules and upset the administration here, but simply because I don't know any equations for this problem.

The Attempt at a Solution



I tried flipping this and finding the cosine of 4pi and graphing it. But I failed to come up with a valid graph and was puzzled. I could take a picture of my "graph", but I don't think anyone could read it. Help would be greatly appreciated here.
"I tried flipping this and finding the cosine of 4pi ..."

That won't work.

sec(θ) = 1/(cos(θ)). It's not equal to cos(1/θ), nor 1/(cos(1/θ)).

Consider the graph of [itex]\displaystyle y=\cos\left(\frac{\pi}{4}x\right)\ .[/itex]

Where does this graph have zeros?

What are the maximum & minimum values for y on this graph?
 

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