1. Writing an equation for an exponential function by



2. A piece of paper that is 0.6 millimeter thick is folded. Write an equation for the thickness t of the paper in millimeters as a function of the number n of folds.
The equation is t(n)=_______________.

3. Enter an equation for the function that includes the points.
(-2, 2/5) and (-1,2)

Respuesta :

Answer: 1) [tex]t(n)=0.6(2)^n[/tex]

2) [tex]f(x)=10(5)^x[/tex]

Step-by-step explanation:

1) Let the function that shows the thickness of the paper after n folds,

[tex]t(n) = ab^n[/tex]         ---------(1)

Since, According to the question,

Initially the thickness of the paper = 0.6

That is, at n = 0, t(0) = 0.6

By equation (1),

[tex]0.6 = a(b)^0\implies 0.6 = a[/tex]

Hence the function that shows the given situation,

[tex]t(n) = 0.6 b^n[/tex]       -----------(2)

Again when we fold the paper the thickness of the paper will be doubled.

Thus, at n = 1, t(1) = 1.2

By equation (2),

[tex]1.2 = 0.6 b^1\implies 2 = b[/tex]

Thus, the complete function is,

[tex]t(n) = 0.6 (2)^n[/tex]    

2) Let the function that is passing through the points (-2, 2/5) and (-1,2),

[tex]f(x) = ab^x[/tex]         ---------(1)

For f(x) = 2, x = -1

By equation (1),

[tex]2= ab^{-1}[/tex]       ---------(2)

Also, For f(x) = 2/5, x = -2

Again, By equation (1),

[tex]\frac{2}{5}= a(b)^{-2}[/tex]

[tex]\implies \frac{2}{5}=ab^{-1}b^{-1}=2b^{-1}[/tex]

[tex]\implies \frac{2}{5}=\frac{2}{b}[/tex]

[tex]\implies 2b=10[/tex]

[tex]\implies b = 5[/tex]

By substituting this value in equation (2),

We get, a = 10

Hence, from equation (1), the function that is passing through the points (-2, 2/5) and (-1,2),

[tex]f(x) = 10(5)^x[/tex]