Finding Function Values on a Graph: f(30) and f(-14) Explained

[Sonny18n]

1. Homework Statement
A graph of y=f(x) is shown. Find the following function values and justify your answers.

f(30)=
f(-14)=

Homework Equations

The Attempt at a Solution

I know the graph is periodic, I know it's max and min, and I know it's amplitude because of that. But I don't know what the 30 or -14 is supposed to mean to me or how I'm suppose to "justify" my answer[/B]

 

[Dick]

View attachment 80886 1. Homework Statement
A graph of y=f(x) is shown. Find the following function values and justify your answers.

f(30)=
f(-14)=

Homework Equations

The Attempt at a Solution

I know the graph is periodic, I know it's max and min, and I know it's amplitude because of that. But I don't know what the 30 or -14 is supposed to mean to me or how I'm suppose to "justify" my answer[/B]

It looks to me like what you are supposed to conclude from the graph is that f(x+4)=f(x). That's periodic. So f(-14)=f(-10)=f(-6)=f(-2). The last value you can read off from the graph. Patterns like that.

 

[Pierce610]

f(30) and f(-14) are the values of the function calculated in x=30 and x=-14.
You said that the graph is periodic, so it means that the graph repeat itself with perod 5.
now you should obtain the two values.

 

[Pierce610]

Yes, Dick is right, the period is 4

 

[SammyS]

Yes, Dick is right, the period is 4

(It is possible for you to Edit post #3. )

 

[Pierce610]

Now no more; I'll do it in future if I should realize in time to have to correct my post