Question

Cosine Function Help

Answer 1

@jim_thompson5910 please help me understand how to find the period

Answer 2

@robtobey

Answer 3

How long does it take to go from the min length to the max length?

Answer 4

2 seconds

Answer 5

It will take another two seconds to go from max to min

Answer 6

So the period is 2*2 = 4 seconds

Basically it starts at the min length and it takes 4 seconds to get back to the min length (where the whole cycle will repeat over again)

Answer 7

hold on ill post the answer choices

Answer 8

Which of those functions has a period of 4?

Answer 9

pi/2

Answer 10

so its A

Answer 11

Hmm that's the thing, it's either A or B

the problem is that I think something is missing from either one

Answer 12

well the difference between the lengths is 14 inches so the amplitude is 7 right?

Answer 13

@jim_thompson5910 ?

Answer 14

Oh I see now

Answer 15

It goes from 6 ft 2 in to 7 ft 4 in

that's a change in 14 inches

Answer 16

Cut that in half to get 14/2 = 7

So 7 is the amplitude

Answer 17

awesome thank you! can you help me with one more? I'm having a difficult time understanding cosine functions...

Answer 18

Alright go ahead

Answer 19

how far did you get?

Answer 20

aren't I supposed to type two functions into a graphing calculator and then find out where the two intersect?

Answer 21

that's one good way to do it

Answer 22

but i can't figure out which two functions I'm supposed to type in

Answer 23

type in y1 = 2*cos(x) and y2 = 1

each side forms its own equation

Answer 24

but how did you figure out to do that?

Answer 25

say you had x+4 = 26

you would break up the equation into two separate equations

y = x+4
y = 26

and graph each one. Where they intersect will tell you the solution

Answer 26

oooohhhhhh now I get it so its B Thank you so much!!!!!

Answer 27

Nice work.