OpenStudy (anonymous):

Identify the maximum and minimum values of the function y = 3 cos x in the interval [-2π, 2π]. Use your understanding of transformations, not your graphing calculator.

5 years ago
OpenStudy (anonymous):

@amistre64, @UnkleRhaukus, @Hero, @jhonyy9. Please help!

5 years ago
OpenStudy (anonymous):

find the derivative first

5 years ago
OpenStudy (anonymous):

Anyone!

5 years ago
OpenStudy (anonymous):

What is the derivative?

5 years ago
OpenStudy (anonymous):

derivative of y = -3sinx

5 years ago
OpenStudy (anonymous):

Well what do I do to find it?

5 years ago
OpenStudy (anonymous):

you didn't learn derivative?

5 years ago
hero (hero):

She's only 14

5 years ago
OpenStudy (anonymous):

I'm sure I did, but I can't remember.

5 years ago
OpenStudy (anonymous):

um... then

5 years ago
OpenStudy (anonymous):

lol How did yo know?

5 years ago
OpenStudy (anonymous):

that's a cosine curv eright?

5 years ago
OpenStudy (anonymous):

*you

5 years ago
OpenStudy (anonymous):

Yes.

5 years ago
OpenStudy (anonymous):

cosine curve has one cycle from -2pie to 0 and another from 0 to 2pie

5 years ago
OpenStudy (anonymous):

Okay.

5 years ago
OpenStudy (anonymous):

usually the highest value of cosine is 1 but since the function is scaled by 3, it'd be 3

5 years ago
OpenStudy (anonymous):

Okay, and the lowest value would be -3, right?

5 years ago
OpenStudy (anonymous):

yeah

5 years ago
OpenStudy (anonymous):

it would go up and down between -3 and 3

5 years ago
hero (hero):

|dw:1355157410446:dw|

5 years ago
OpenStudy (anonymous):

So is that the answer? Are those the minimum and maximum values?

5 years ago
OpenStudy (anonymous):

yeah but why don't u take a look at cosine and since curve

5 years ago
OpenStudy (anonymous):

y = sinx and y =cosx

5 years ago
OpenStudy (anonymous):

it'd make more sense afterwards

5 years ago
OpenStudy (anonymous):

When it talks about the interval (-2pi, 2pi), does that affect the answer that I write?

5 years ago
OpenStudy (anonymous):

if you have a shorter interval, say pie/2 to pie, your maximu value won't be three

5 years ago
OpenStudy (anonymous):

bye

5 years ago
OpenStudy (anonymous):

Wait! @hcmathkim! Will the interval be longer or shorter, and how do I find the maximum value and minimum value from that?

5 years ago
OpenStudy (anonymous):

@Hero I really don't know what to write. Please help me.

5 years ago
OpenStudy (anonymous):

Is the answer 3 and -3, or does the interval affect it?

5 years ago
OpenStudy (anonymous):

highest values of cosine curve occurs at x = 2n(pie) , n = any integer

5 years ago
hero (hero):

Just because you can't use your calc, that doesn't mean you can't imagine what it looks like in your head.

5 years ago
OpenStudy (anonymous):

i meant 2n (2pie)

5 years ago
OpenStudy (anonymous):

So would n be 3?

5 years ago
OpenStudy (anonymous):

come on.. go look at the cosine curve..

5 years ago
OpenStudy (anonymous):

it will help

5 years ago
OpenStudy (anonymous):

Okay, I looked at it but I don't know how that's going to help me find the answer. I am really confused.

5 years ago