Answer:
[tex]x = [2644,8418)[/tex]
Step-by-step explanation:
Given
[tex]f(x) = 86.3ln\ x - 680[/tex]
[tex]x < 8418[/tex]
Required
The domain of the function
The maximum value of x has been given.
So, the next step is to calculate its minimum value.
Since f(x) represents the % moisture. This value cannot go less than 0.
So, we set f(x) to 0; in order to calculate the minimum of x.
This gives:
[tex]f(x) = 0[/tex]
[tex]86.3ln\ x - 680 = 0[/tex]
Add 680 to both sides
[tex]86.3ln\ x - 680 + 680= 0 + 680[/tex]
[tex]86.3ln\ x = 680[/tex]
Divide both sides by 86.3
[tex]ln\ x = \frac{680}{86.3}[/tex]
[tex]ln\ x = 7.88[/tex]
Take exponent of both sides
[tex]e^{(ln\ x)} = e^{7.88[/tex]
[tex]x = e^{7.88[/tex]
[tex]x = 2644[/tex]
Hence, the domain is:
[tex]x = [2644,8418)[/tex]
or
[tex]2644 \le x< 8418[/tex]