A logarithmic function is expressed as
y = a + blnx
We would substitute corresponding values of x and y into the function. This will give us two equations. We would solve the equations for a and b. We have
From the table, when x = 1, y = 60
Thus,
60 = a + b * ln1
60 = a + b * 0
60 = a
when x = 2, y = 54
Thus,
54 = a + bln2
54 = a + 0.693b
Substituting a = 60 into 54 = a + 0.693b, we have
54 = 60 + 0.693b
0.693b = 54 - 60 = - 6
b = - 6/0.693
b = - 8.65
The function would be
f(x) = 60 - 8.65lnx
