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Solve the initial value problem. dy/dx=2xy, y(0)=3.

2 Answers

4 votes

Final answer:

The initial value problem dy/dx = 2xy, y(0) = 3 is solved by separating variables, integrating both sides, finding the integration constant using the initial condition, and then expressing y explicitly. The final solution is y = 3e^(x^2).

Step-by-step explanation:

We need to solve the initial value problem given by the differential equation dy/dx = 2xy, with the initial condition y(0) = 3. This is a separable differential equation, so we can separate variables and integrate both sides. The solution involves integrating the derivative of y with respect to x and using integration techniques to solve it.

  1. Separate the variables: dy/y = 2x dx.
  2. Integrate both sides: ∫ dy/y = ∫ 2x dx which gives ln|y| = x² + C.
  3. Using the initial condition, we find C: ln|3| = 0² + C, thus C = ln(3).
  4. Now we have the particular solution: ln|y| = x² + ln(3).
  5. Exponentiate both sides to solve for y: y = e² + ln(3) or y = 3e².

The final solution to the initial value problem is y = 3e².

User Jeff Parker
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8.3k points
4 votes

Final Answer:

The solution to the initial value problem
\( (dy)/(dx) = 2xy \), with the initial condition
\( y(0) = 3 \), is \( y(x) = 3e^(x^2) \).

Step-by-step explanation:

To solve the given initial value problem, we can use separation of variables. Start by separating variables and integrating both sides:


\[ (1)/(y) \, dy = 2x \, dx \]

Integrate both sides:


\[ \ln|y| = x^2 + C \]

Now, apply the initial condition
\( y(0) = 3 \):


\[ \ln|3| = 0 + C \]


\[ C = \ln|3| \]

Substitute
\( C \) back into the equation:


\[ \ln|y| = x^2 + \ln|3| \]

Exponentiate both sides:


\[ |y| = 3e^(x^2) \]

Consider the absolute value, and since
\( y(0) = 3 \) is positive:


\[ y(x) = 3e^(x^2) \]

This is the solution to the initial value problem. The exponential term
\( e^(x^2) \) reflects the growth of the solution, and the initial condition ensures that the constant
\( C \) is determined, resulting in the specific solution
\( y(x) = 3e^(x^2) \).

User Rala
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8.2k points