Write the exponential function y - 45(1.085)^t in the form y = ae^kt(a) Once you have rewritten the tormula, give & accurate to at least four decimal places.K=If T is measured in years, indicate whether the exponential function is growing or decaying and find he annual and continuous growth/decay rates. The rates you determine should be positive in the case of growth or decay (by choosing decay the negative rate is implied).(b) The annual (growth/decay) rate is ___ % per yearC) The continuous (growth/decay) rate is ___ % per year

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EXPLANATION

Given the exponential function:

45(1.085)^t

We have that 45=a is the initial value and 1.085 is the growth rate,

1.085 - 1 = 0.085* 100 = 8.5 % (This is the growth rate)

Let's compute the function with two values of t, as for instance, t=0 and t=1:

[tex]f(0)=45(1.085)^0=45\cdot1=45\longrightarrow\text{ (0,45)}[/tex][tex]f(1)=45\cdot(1.085)^1=48.825\text{ }\longrightarrow\text{(1,48.825)}[/tex]

Now, the function in the form y = ae^kt will be as follows:

[tex]y=45\cdot e^{kt}[/tex]

Substituting t by 1:

[tex]y(1)=45\cdot e^k=48.825[/tex]

Dividing both sides by 45:

[tex]e^k=\frac{48.825}{45}=1.085[/tex]

Applying ln to both sides:

[tex]k=\ln 1.085[/tex]

Computing the argument:

[tex]k=0.0816[/tex]

The expression will be as follows:

[tex](a)---\longrightarrow y=45e^{0.0816t}[/tex]

As this is a growing function, the rates are positive.

The annual growth rate is 8.5% and It's was calculated above.

Now, we need to compute the continuous rate because It's given by the value of k:

k = 0.0816 --> Multiplying by 100 --> 0.0816 * 100 = 8.16%

The continuous growth rate is 8.16%