(Differential equation) Finding an exponential equation

In summary, the conversation discusses a 44 gallon barrel of oil with a leak at the bottom and a mathematical model, A(t), representing the amount of oil in the barrel at a given time t. It is stated that the rate of decrease of oil is proportional to the product of time elapsed and the amount of oil present. The conversation then goes on to discuss finding the general and particular solutions for the differential equation and the initial condition. The resulting solutions are given as A(t)=Ce^(-kt^2/2) and A(t)=44e^(-kt^2/2).
  • #1
namegoeshere
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Homework Statement



A 44 gallon barrel of oil develops a leak at the bottom. Let [itex]A(t)[/itex] be the amount of oil in the barrel at a given time [itex]t[/itex]. Suppose that the amount of oil is decreasing at a rate proportional to the product of the time elapsed and the amount of oil present in the barrel.

a. Give the mathematical model for A
b. Find the general solution of the differential equation
c. Find the particular solution for the initial condition

Homework Equations


The Attempt at a Solution


a.
[itex]\frac{\partial{A}}{\partial{t}} = -Akt[/itex]​
b.
[itex]\int{\frac{1}{A}\,dA} = \int{-kt\,dt}[/itex]
[itex]\ln{A}=\frac{kt^2}{2}+C[/itex]
[itex]A(t)=Ce^\frac{-kt^2}{2}[/itex]​
c.
[itex]44=Ce^0[/itex]
[itex]A(t)=44e^\frac{-kt^2}{2}[/itex]​

Is this correct? I'm not sure if I came up with the right [itex]\frac{\partial{A}}{\partial{t}}[/itex].
 
Last edited:
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  • #2
All looks right to me.
 

1. How do I determine if a given differential equation can be solved with an exponential equation?

To determine if a differential equation can be solved with an exponential equation, you need to check if the equation is in the form of dy/dx = ky, where k is a constant. If the equation follows this form, then it can be solved using an exponential equation.

2. What is the general form of an exponential differential equation?

The general form of an exponential differential equation is dy/dx = ky, where k is a constant.

3. How do I solve an exponential differential equation?

To solve an exponential differential equation, you need to separate the variables and integrate both sides. This will give you the general solution in the form of y = Cekx, where C is a constant and k is the coefficient of y.

4. Can an exponential equation be used to model real-life situations?

Yes, exponential equations can be used to model real-life situations, such as population growth, radioactive decay, and compound interest.

5. Are there any limitations to using an exponential equation to solve differential equations?

Yes, there are limitations to using an exponential equation to solve differential equations. Exponential equations can only be used for linear differential equations and may not be applicable for nonlinear equations. Additionally, the solutions for exponential equations may not always be accurate for real-life situations due to simplifications made in the modeling process.

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