A 2-column table has 5 rows. The first column is labeled x with entries negative 2, negative 1, 0, 1, 2. The second column is labeled f (x) with entries 12. 5, 2. 5, 0. 5, 0. 1, 0. 2. Which exponential function is represented by the table? f(x) = 0. 2(0. 5x) f(x) = 0. 5(5x) f(x) = 0. 5(0. 2x) f(x) = 0. 2(0. 2x).

Respuesta :

An exponential function is characterized by an initial value, and an exponential rate

The function f(x) is [tex]\mathbf{f(x) =0.5(0.2)^x}[/tex]

f(x) is an exponential function that passes through points (-2,12.5), (-1,2.5), (0,0.5), (1,0.1) and (2,0.2).

An exponential function is represented as:

[tex]\mathbf{y = ab^x}[/tex]

At point (0,0.5), we have:

[tex]\mathbf{0.5 = ab^0}[/tex]

This gives

[tex]\mathbf{0.5 = a \times 1}[/tex]

[tex]\mathbf{0.5 = a}[/tex]

Rewrite as:

[tex]\mathbf{a = 0.5 }[/tex]

At point (-1,2.5), we have:

[tex]\mathbf{2.5 = ab^{-1}}[/tex]

Substitute 0.5 for a

[tex]\mathbf{2.5 = 0.5b^{-1}}[/tex]

Divide both sides by 0.5

[tex]\mathbf{5 = b^{-1}}[/tex]

Take inverse of both sides

[tex]\mathbf{\frac 1{5} = b}[/tex]

Rewrite as:

[tex]\mathbf{b = \frac 1{5} }[/tex]

[tex]\mathbf{b = 0.2}[/tex]

So, we have:

[tex]\mathbf{b = 0.2}[/tex] and [tex]\mathbf{a = 0.5 }[/tex]

Substitute these values in [tex]\mathbf{y = ab^x}[/tex]

[tex]\mathbf{y =0.5(0.2)^x}[/tex]

Express as a function

[tex]\mathbf{f(x) =0.5(0.2)^x}[/tex]

Hence, the function f(x) is [tex]\mathbf{f(x) =0.5(0.2)^x}[/tex]

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