Math Problem Statement

Is y = -2/3x + 1/9 a solution to the differential equation y' = 2x + 3y - 1?

Solution

The problem in the image asks if the function y=23x+19y = -\frac{2}{3}x + \frac{1}{9} is a solution to the differential equation y=2x+3y1y' = 2x + 3y - 1.

To determine if this is a solution, we will:

  1. Differentiate y=23x+19y = -\frac{2}{3}x + \frac{1}{9} to find yy'.
  2. Substitute yy and yy' into the given equation y=2x+3y1y' = 2x + 3y - 1 and check if both sides are equal.

Let's start by differentiating y=23x+19y = -\frac{2}{3}x + \frac{1}{9}:

dydx=23\frac{dy}{dx} = -\frac{2}{3}

Now, substitute y=23x+19y = -\frac{2}{3}x + \frac{1}{9} and y=23y' = -\frac{2}{3} into the differential equation:

y=2x+3y1y' = 2x + 3y - 1

Substituting:

23=2x+3(23x+19)1-\frac{2}{3} = 2x + 3\left( -\frac{2}{3}x + \frac{1}{9} \right) - 1

Simplifying the right side:

23=2x2x+131-\frac{2}{3} = 2x - 2x + \frac{1}{3} - 1

23=131-\frac{2}{3} = \frac{1}{3} - 1

23=23-\frac{2}{3} = -\frac{2}{3}

Since both sides are equal, the function y=23x+19y = -\frac{2}{3}x + \frac{1}{9} is indeed a solution to the given differential equation.

Thus, the correct answer is: A) Yes

Do you want further explanation or details on the steps? Here are some additional questions that may be helpful:

  1. What is the general method for solving first-order linear differential equations?
  2. How would the solution change if the equation was non-linear?
  3. How do we determine if a given function is a solution to a differential equation?
  4. What is the significance of differentiating functions in solving differential equations?
  5. How can we verify if multiple functions are solutions to the same equation?

Tip: Always simplify both sides of the equation after substitution to make it easier to compare both sides!

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Math Problem Analysis

Mathematical Concepts

Differential Equations
Derivative
Substitution

Formulas

y' = 2x + 3y - 1
y = -2/3x + 1/9

Theorems

Method of verifying solutions to differential equations

Suitable Grade Level

Grades 10-12