Evaluate the function for the elements in the domain {-4,-2,0,2,4}. This is the function: f(x)=2x-1

Question

I don't know what they want for an answer or even the steps to solve it. Please explain it in as much detail as possible.

Answer 1

A function is a paired set with elements in the domain and elements in the target space. Note we are only going to apply numbers in the domain set

f(-4) = 2(-4) - 1 = -8 - 1 =-9

f(-2) = 2(-2) - 1 = -4 - 1 =-5

f(0) = 2 (0) - 1 = 0 -1 = -1

f(2) = 2(2) -1 = 4-1 = 3

f(4) = 2(4) -1 = 8 -1 = 7

So the function set is {(-4,-9), (-2,-5), (0,-1), (2,3), (4,7)}

The curly bracket shows what is in the set and each pair has the domain (input) number first and the target (output) number second. We don't usually write out the sets for an infinite or continuous domain because that's too much work.

Answer 2

If I understand your question correctly, it is asking to evaluate the function f at the values in the set {-4,-2,0,2,4}.

I will write a similar example (it is not the same problem!) so that you can solve your problem on your own.

New Problem Let's evaluate the function f(x)=3x+1 in the domain {0,1,-1}.

Solution We replace one by one x with each of the values in the domain. The values in the domain are 0,1 and -1. Thus,

f(0) = 3(0)+1 = 0+1 = 1

f(1) = 3(1)+1 = 3+1 = 4

f(-1) = 3(-1)+1 = -3+1 = -2

Hence, f(0)=1, f(1)=4 and f(-1)=-2.

Hope this helps! Good luck!

Answer 3

Hi Alia,

The domain of a function is the set of x coordinates that we can input into the function to get valid y coordinates.

For instance, for the function f(x) = 2x-1, we can input any x and we will get some number y. Inputting x = 3 gives f(3) = 2*3 - 1 = 5. We say that we are evaluating the function at x = 3.

In this case, although one could put any real number x into f(x), the question is just asking you to evaluate the function for just the handful of numbers in the brackets. We do this by plugging each value into the f(x) and simplifying. Thus,

f(-4) = 2*(-4) - 1 = -9

f(-2) = 2*(-2) - 1 = -5

f(0) = 2*0 - 1 = -1

f(2) = 2*2 - 1 = 3

f(4) = 2*4 - 1 = 7

Let me know if this helps and if there is anything else I can help with!

Alexis