
Steven C. answered 11/25/15
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Mathematics Tutor Steven
The model follows the equation:
y = C*e^(k*t)
thus the ratio of two y values in the data is:
y1/y2 = e^(k*t1)/e^(k*r2)
The ratio of two exponentials is the difference of the exponential arguments, so:
y1/y2 = e^(k*(t1 - t2))
=> 4/9 = e^(k*(-2))
=> -2*k = ln(4/9)
=> k = 0.4055.
substitute the value of k into either equation to solve for C.
7.5 = C*e^(0.4055*1)
=> 7.5 = C*1.5
=> C = 5.
thus, the exponential function would be:
y = 5*e^(0.4055*t).