Solving a Second-Order Differential Equation: y" - 3y' - 10y = 1

Published on May 29, 2025

Calculus

Find the solution y(t) to the second-order linear non-homogeneous differential equation y" - 3y' - 10y = 1 with initial conditions y(0) = -1 and y'(0) = 2. The solution involves finding the complementary and particular solutions and applying initial conditions.

Question

Answer

The problem asks us to find the solution to the given initial value problem (IVP):
with initial conditions and .
This is a second-order linear non-homogeneous differential equation with constant coefficients. The general solution can be found by summing the complementary solution and a particular solution , i.e., .
Step 1: Find the complementary solution .
The homogeneous equation is .
The characteristic equation is .
We can factor this quadratic equation:
The roots are and .
Since the roots are real and distinct, the complementary solution is:
where and are arbitrary constants.
Step 2: Find a particular solution .
Since the right-hand side of the non-homogeneous equation is a constant, , we can assume a particular solution of the form , where is a constant.
Then, and .
Substitute these into the non-homogeneous equation:
So, the particular solution is .
Step 3: Form the general solution.
The general solution is :
Step 4: Apply the initial conditions to find and .
We have and .
First, let’s find :
Now, apply the initial conditions:
For :
For :
Now we have a system of two linear equations with two variables and :
From equation (1), . Substitute this into equation (2):
Now substitute back into :
To subtract these fractions, find a common denominator, which is 70:
Step 5: Write the final solution .
Substitute the values of and into the general solution:
The final answer is .