Math Problem Statement

Solve this step by step correctly

Shown below is the slope field for which differential equation? Options: (A) dy/dx = 1 + y^2, (B) dy/dx = x - y, (C) dy/dx = 1 + x^2, (D) dy/dx = 1 - y^2 + x^2.

Solution

Step-by-Step Solution:

We need to identify the correct differential equation from the slope field shown in the image.

The slope field is determined by the differential equation dydx=f(x,y)\frac{dy}{dx} = f(x, y), where f(x,y)f(x, y) represents the slope at any given point (x,y)(x, y).

Observing the Slope Field:

  1. Horizontal slopes (dy/dx = 0): The slope lines appear horizontal along the xx-axis (y=0y = 0).

    • This suggests that f(x,y)=0f(x, y) = 0 when y=0y = 0.
  2. Slope behavior with xx and yy:

    • Above the xx-axis (y>0y > 0), the slope increases (positive).
    • Below the xx-axis (y<0y < 0), the slope decreases (negative).
  3. Symmetry: The slope pattern seems symmetric in both quadrants above and below the xx-axis, indicating that the equation might include terms like y2y^2, which is symmetric about the xx-axis.

Testing Each Option:

We evaluate the given options against the slope field:

(A) dydx=1+y2\frac{dy}{dx} = 1 + y^2:

  • At y=0y = 0, dydx=1\frac{dy}{dx} = 1. This implies a uniform slope of 1 along the xx-axis.
  • The slope in the field at y=0y = 0 appears constant but NOT 1 everywhere. Eliminate (A).

(B) dydx=xy\frac{dy}{dx} = x - y:

  • At y=0y = 0, dydx=x\frac{dy}{dx} = x, meaning the slope varies linearly with xx.
  • At x=0x = 0, dydx=y\frac{dy}{dx} = -y, which means the slope becomes negative below the xx-axis and positive above.
  • This fits the slope behavior in the field. Possible answer.

(C) dydx=1+x2\frac{dy}{dx} = 1 + x^2:

  • At y=0y = 0, dydx=1+x2\frac{dy}{dx} = 1 + x^2, which gives a parabola-like slope pattern along the xx-axis.
  • This does NOT match the observed field, where slopes along y=0y = 0 are not parabolic. Eliminate (C).

(D) dydx=1y2+x2\frac{dy}{dx} = 1 - y^2 + x^2:

  • At y=0y = 0, dydx=1+x2\frac{dy}{dx} = 1 + x^2, which again suggests a parabolic slope pattern.
  • This does NOT match the slope field. Eliminate (D).

Conclusion:

The correct answer is (B) dydx=xy\frac{dy}{dx} = x - y, as it aligns with the slope patterns observed in the field.


Let me know if you need further explanation!

Here are 5 related questions you can try:

  1. How do slope fields visually represent solutions to differential equations?
  2. How can you sketch a slope field given a differential equation?
  3. What does symmetry in a slope field tell us about the differential equation?
  4. How does the behavior of dydx\frac{dy}{dx} at y=0y = 0 help narrow down the options?
  5. How can you verify the correctness of a solution to a slope field problem?

Tip: Always look for key features like horizontal slopes, symmetry, and patterns along axes when matching slope fields to equations.

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Math Problem Analysis

Mathematical Concepts

Differential Equations
Slope Fields
Symmetry in Graphs

Formulas

dy/dx = f(x, y)

Theorems

Slope Fields Correspond to Differential Equations
Symmetry Properties in Functions

Suitable Grade Level

Undergraduate (Calculus 1/2)