Question

Find the domain, period, range, and amplitude of the cosine function.

y = -6cos4x

Answer 1

I have 4 choices, but I think it's this one.

Answer 2

domain = all real numbers; period = 1/2 ; range:-6<y<6 ; amplitude = -6

Answer 3

Domain will always be \[(-\infty, \infty)\]

Answer 4

amplitude can never be negative

Answer 5

and you missed a pi in the period :)

Answer 6

omain = all real numbers; period = 1/2 ; range:-6<y<6 ; amplitude = 6

This is another choice. And none of them have pie.

Answer 7

\[Period \frac{ 2\pi }{ (bx) }\]

Answer 8

I agree with the others. Here's a good site for identifying the parts!
http://www.regentsprep.org/Regents/math/algtrig/ATT7/sinusoidal.htm
Is says the amplitude will be the absolute value of what's multiplying the \(cos()\) function. Sorry to mislead you earlier!

Answer 9

Yes what @theEric said about the abs calue on it and also amp is the number next to the sin so is it -6 or 6, there's a differnce in those two answers don't get tripped up

Answer 10

:) you must have the pi for the period

cos(4x) runs 4 times faster than cos(x)

since cos(x) period is 2pi,
cos(4x) period wud be 2pi/4 = pi/2

Answer 11

The period should be \(\LARGE \frac{2\pi}{4}=\frac{\pi}{2}\)...

Answer 12

I'm guessing its something weird with the problem and its choices...

Answer 13

How do you get your equation to be so big @theEric

Answer 14

I had a Pennsylvania standardized test not have a \(\pm\) option when solving for \(x\) under a radical...

Answer 15

Heres a screenshot of the exact problem.

Answer 16

go with B @ExplainItLikeImFive

Answer 17

Well @ExplainItLikeImFive If you know teh amplitude is -6 and the domain is ARN and there's only one option with those two specifications, there's no need to calculate the rest of them if you already know how to find them (test taking tip)

Answer 18

When you're in the `\[ \]` or `\( \)`, use `\large`, `\Large`, `\LARGE`, `\huge`, or `\Huge`. They get bigger as you go along.

Answer 19

Go with C the amplitude is -6 not 6 @ganeshie8

Answer 20

Thanks!

Answer 21

amplitude is the distance from average value
so u have to take the absolute value of the quantity next to cos
amplitude = |-6| = 6

Answer 22

Amplitude is \(\left|-6\right|=6\), conventionally.

Answer 23

My bad, ha, abs values always get me x.x

Answer 24

@doulikepiecauseidont and you can use `\tiny`, `\Tiny`, `\small`, and `\normalsize` too.

Answer 25

Haha!

Answer 26

Thanks to you all.

Answer 27

np :)

Answer 28

My only regret is I cant give all of you a medal.

Answer 29

\[\Huge wow this is cool \]

Answer 30

How about we al;l give each other one?

Answer 31

I know the feeling. They got to it first, so that helps narrow it down!

Answer 32

Alright, we can try that! :)

Answer 33

I christen @ganeshie8

Answer 34

Alright! And he got me and I got doulikepiecauseidont.

Answer 35

ganeshie must get ExplainItLikeImFive.

Answer 36

thank you :) @doulikepiecauseidont give it to @ExplainItLikeImFive then we all are even :)

Answer 37

I did give it to him

Answer 38

Someone already got you, thats why you hahve two

Answer 39

I clicked the wrong one the first time, but then I got ExplainItLikeImFive , now it's still uneven...

Answer 40

Well i picked @ganeshie8 and so did @ExplainItLikeImFive

Answer 41

So I switch mine to @doulikepiecauseidont

Answer 42

Thats why it was two but ok lets get this

Answer 43

yea thats it

Answer 44

Alright, playing field leveled.

Answer 45

1's across the board.

Success!