Find a solution of the form y1(t) = eat of the equation(3t − 1)y′′ − 9ty′ + 9y = 0,and then use the reduction of order method to find the second linearlyindependent solution.
Question
Find a solution of the form y1(t) = eat of the equation(3t − 1)y′′ − 9ty′ + 9y = 0,and then use the reduction of order method to find the second linearlyindependent solution.
Solution 1
Sure, let's solve this step by step.
Step 1: Find a solution of the form y1(t) = eat
We are given the differential equation (3t − 1)y′′ − 9ty′ + 9y = 0. We are looking for a solution of the form y1(t) = eat.
We can start by finding the derivatives of y1(t):
y1'(t) = a * e^at y1''(t) = a^2 * e^at
Substitute y1(t), y1'(t), and y1''(t) into the differential equation:
(3t - 1) * a^2 * e^at - 9t * a * e^at + 9 * e^at = 0
We can factor out e^at (since e^at ≠ 0):
e^at * [(3t - 1) * a^2 - 9t * a + 9] = 0
Setting the bracketed term equal to zero gives us a quadratic equation in a:
(3t - 1) * a^2 - 9t * a + 9 = 0
Solving this quadratic equation will give us the value of a.
Step 2: Use the reduction of order method to find the second linearly independent solution
The reduction of order method states that if y1(t) is a solution to the differential equation, then the second solution can be found by y2(t) = y1(t) * ∫(e^(-∫p(t) dt) / y1(t)^2) dt, where p(t) is the coefficient of y' in the original differential equation divided by the coefficient of y''.
In this case, p(t) = -9t / (3t - 1).
So, y2(t) = y1(t) * ∫(e^(-∫-9t / (3t - 1) dt) / y1(t)^2) dt
Solving this integral will give us the second solution y2(t).
Solution 2
Sure, let's solve this step by step.
Step 1: Find a solution of the form y1(t) = e^(at)
The given differential equation is (3t - 1)y'' - 9ty' + 9y = 0. We are looking for a solution of the form y1(t) = e^(at).
To find 'a', we substitute y1(t) into the differential equation and solve for 'a'.
y1'(t) = a * e^(at) y1''(t) = a^2 * e^(at)
Substituting these into the differential equation gives:
(3t - 1)a^2 * e^(at) - 9ta * e^(at) + 9e^(at) = 0
Simplifying, we get:
e^(at) * [(3t - 1)a^2 - 9ta + 9] = 0
Since e^(at) is never zero, we can divide both sides by e^(at) to get:
(3t - 1)a^2 - 9ta + 9 = 0
This is a quadratic equation in 'a'. Solving for 'a' gives a = 3t or a = -3.
Step 2: Use the reduction of order method to find the second linearly independent solution.
The reduction of order method states that if y1(t) is a solution to the differential equation, then the second solution can be found by y2(t) = y1(t) * v(t), where v(t) satisfies v'(t) = - (y1''(t) + p(t)y1'(t))/y1(t)^2.
Here, y1(t) = e^(3t) or e^(-3t), and p(t) = -9t/(3t - 1).
Substituting these into the equation for v'(t) and solving gives v(t) = e^(3t) or e^(-3t).
Therefore, the second linearly independent solution is y2(t) = y1(t) * v(t) = e^(6t) or e^(-6t).
Similar Questions
Use the separation of variables method to find the solution of the first-order separable differ-ential equationyx y′ = y2 + 9x2 + 4which satisfies y(0) = 3
(9y - 1)(6y2 - y - 4)= ___A.3y2 - 35y + 4B.54y3 - 15y2 - 35y + 4C.54y3 + 3y2 - 35y + 4D.54y3 - 35y + 4
(9y - 1)(6y2 - y - 4)= ___A.54y3 - 15y2 - 35y + 4B.54y3 - 35y + 4C.54y3 + 3y2 - 35y + 4D.3y2 - 35y + 4
y = c1x + c2x2x2 lnx lnx x, (0, `);x2y0 − xy9 + y = 0, y(1) = 3, y9(1) = −1
10(t+1)dydt−9y=9t,
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