Question

Picture Question Trig Level

Answer 1

I'm psyched. Let's do this.

Answer 2

Well, really all you're concerned with is the period of that sin part of the function.

Answer 3

That is, the sin part of the function really just goes between 1 and -1. If at some time, that part of the function is 1, how much time passes before it is 1 again?

Answer 4

Follow me?

Answer 5

is t = x? if so that would be 2pi/20pi right?

Answer 6

t = x? I'm not sure where x is coming from.

Answer 7

Oh, you mean the x axis on the graph? Yeah, t would be the variable for the x axis.

Answer 8

well im use to seeing these graphs as y= k + Asin (B(x-h)) and the period would be 2pi / B

Answer 9

Ah, I see what you're thinking now. 20pi in this case is your B. t is x.

Answer 10

h is 0, k is 0, A is 35.

Answer 11

yeah i got the amplitude part i dunno whats going on with the 20 pi t part

Answer 12

When t is 0, sin(20pi*t)=0, right?

Answer 13

What does 20pi*t need to be to make sin(20pi*t) 0 again?

Answer 14

but its not 0 its 0.5 right?

Answer 15

or would it be 0.5/60 since its in seconds

Answer 16

Ignore that .5 business for now. First let's just figure out the period of the function.

Answer 17

mk

Answer 18

The idea is that they want to know what makes sense as time interval to use when graphing the function. A good time interval to use is one that is the period of the function or maybe half of the period.

Answer 19

So first we're going to figure that period out and then we'll compare it to the .5 second that he tried to use as a period. Make sense?

Answer 20

yes sir

Answer 21

Alright cool. Well let me ask again then. At time 0, the function starts at 0. When is the next time that the function would be 0?

Answer 22

Sin(pi) =?

Answer 23

0

Answer 24

Riiiight. Sooo when is 20pi * t = pi?

Answer 25

when time is 0

Answer 26

Nope. When time is 0, 20pi*t = 0.

Answer 27

Try again. When is 20pi*t = pi?

Answer 28

but its sin 0

Answer 29

I know that sin(20pi*t) is 0 when t is 0 because 20pi*t is 0 and sin(0) is 0. However, I want to know the next time that sin(20pi*t) is 0, which happens when 20pi*t is pi.

Answer 30

well then t would be like .05

Answer 31

For visual.

Answer 32

Yes =) When t = 1/20 = .05

Answer 33

So the graph does that every .05 seconds. You tell me whether or not .5 is a good increment for the axis then.

Answer 34

.5 is terrible because you would get so many waves

Answer 35

Exactly. =)

Answer 36

And what would be a better choice?

Answer 37

interesting way i had no clue where you going with this then it all came together xD

Answer 38

.1

Answer 39

Haha yeah. Sorry I wasn't making it very clear to start with.

Answer 40

Yeah. .1 or .05 would borh work well.

Answer 41

lol crazy well now i know why i missed that question

Answer 42

thanks for the help buddy