Question

graphing cosine functions help! http://puu.sh/3byUE.png

Answer 1

I know that the period is 2 and the amplitude is 2. And i know that the cosine function is going to start with y = 2cos but I'm not sure how to finish it. And I also have no idea how to do part b.

Answer 2

@dan815

Answer 3

and are you sure? the graph seems a bit condensed

Answer 4

i thought so. i know that the amplitude is the first number in a cosine function
y = a cos b x, where a = amplitude

Answer 5

Well the amp is right for sure

Answer 6

if the amplitude is correct, then the period is correct too, right?

Answer 7

The period is determined by the number in front of the x right?

Answer 8

if i use 2 cos 2x and check it with another graph it doesn't look right though :(

Answer 9

That's cause the equation is actually 2cos4x

Answer 10

can you tell me how you found that?

Answer 11

It was more of a trial and error thing, first I tried 2cos .5x, which turned out to be a bit big, so i did 2cos2x, and finally 2cos4x

Answer 12

awesome. thank you so much.

Answer 13

and btw the period is pi/2

Answer 14

Do you need help with part b or do you got that?

Answer 15

if you can help me that'd be great. i've never solved a question like it before.

Answer 16

the question is basically asking, where does the graph have it's lowest and highest points between 2pi. And where it crosses the x-axis

Answer 17

THe period is pi/2

Answer 18

lowest point is -2, highest point is 2, and crosses the x axis between 3/8pi, right?

Answer 19

That has already been mentioned, but thank you professor

Answer 20

Crosses the X axis every pi/4 starting at pi/8

Answer 21

He can walk you through part b Megan, good luck!

Answer 22

No he can xD I'm going back to Pawn Stars!

Answer 23

thanks @Luigi0210!
@FutureMathProfessor so how would i represent that in the inequality?

Answer 24

haha have fun :)

Answer 25

aw come on, I don't really know how to explain it.. @FutureMathProfessor

Answer 26

Max: pi/2, pi, 3pi/2, 2pi
Min: pi/4, 3pi/4, 5pi/4, 7pi,4
Zero: pi/8, 3pi/8, 5pi/8, 7pi/8, 9pi/8, 11pi/8, 13pi/8, 15pi/8

Answer 27

and I didn't give you a mesal for nothing

Answer 28

*medal

Answer 29

Me neither

Answer 30

Thank you

Answer 31

But yea, that's your answer megan ^_^'

Answer 32

thanks a lot guys!

Answer 33

Medal me

Answer 34

too late, I got it :D

Answer 35

Take his medal away and medal me instead :D

Answer 36

aw, that would make me upset -_-