Identify the maximum and minimum values of the function y = 10 cos x in the interval [-2π, 2π]. Use your understanding of transformations, not your graphing calculator.

Question

anonymous · Answer

What would y=cos(x) look like without the 10 in front?

anonymous · Answer

What do you mean?

anonymous · Answer

Have you seen a graph of y=cos(x) before?

anonymous · Answer

Yes

anonymous · Answer

What does it look like? What are the maximum and minimum values of it and why?

anonymous · Answer

The maximum is the hill and the minimum is the valley

anonymous · Answer

Right, but what are the values? What is the cosine of 0? What is the cosine of π/2? What is the cosine of π? or 3π/2? or of 2π?

anonymous · Answer

There isn't a graph for this,, I have no idea how to do this question. That's why i am asking :o

anonymous · Answer

You need to understand these basic concepts before you can attempt a more detailed question like the one you posted. I'm trying to make sure you know what a cosine is.

anonymous · Answer

You can draw the graph yourself.

anonymous · Answer

There is no graph to draw. I am learning this all in one lesson on an online class. I don't want you to give me the exact answer.. maybe just explain it so I can understand what I am doing? We don't have to draw the graph, we must explain the transformations. I think you realize my confusion when that big of a question is asked when you just learned it

anonymous · Answer

Right, that's why I want to make sure you have a strong foundation in the basics before moving on to the more advanced stuff.

anonymous · Answer

but so you will even begin to help me, the maximum is 2pi the minimum is pi i believe

anonymous · Answer

I'm sure you've drawn graphs yourself before. you make a table of x and y values, then plot them on a coordinate grid.
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anonymous · Answer

Are you familiar with the concept of the unit circle?

anonymous · Answer

Yes

anonymous · Answer

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anonymous · Answer

Ok, use the unit circle to find the cosine of the following angles:

x=Θ | y=cos(Θ)

0
π/2
π
3π/2
2π

anonymous · Answer

You want me to draw a graph correct?

anonymous · Answer

Or at least imagine what it looks like after you've figured out where the minimum and maximum y-values are.

anonymous · Answer

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