1. Fundamental Concepts
- Definition: Inverse Variation describes a relationship between two variables where their product is always a constant, denoted as $$K$$ . Mathematically, if $$x$$ and $$y$$ are inversely proportional, then $$xy = K$$ .
- Constant of Variation: The constant $$K$$ in the equation $$xy = K$$ represents the product of the two variables and remains unchanged regardless of the values of $$x$$ and $$y$$ .
- Graphical Representation: The graph of an inverse variation is a hyperbola with asymptotes at the coordinate axes.
2. Key Concepts
Basic Rule: $$xy = K$$
Degree Preservation: The product of the variables remains constant regardless of their individual values.
Application: Used to model relationships where one variable increases while the other decreases proportionally.
3. Examples
Example 1 (Basic)
Problem: If $$x$$ and $$y$$ are inversely proportional and $$x = 4$$ when $$y = 6$$ , find the constant of variation $$K$$ .
Step-by-Step Solution:
- Substitute the given values into the equation $$xy = K$$ : $$4 \cdot 6 = K$$
- Solve for $$K$$ : $$K = 24$$
Validation: Substitute $$x=4$$ and $$y=6$$ → Original: $$4 \cdot 6 = 24$$ ; Simplified: $$K = 24$$ ✓
Example 2 (Intermediate)
Problem: Given that $$xy = 30$$ , find $$y$$ when $$x = 5$$ .
Step-by-Step Solution:
- Substitute the known values into the equation $$xy = K$$ : $$5y = 30$$
- Solve for $$y$$ : $$y = \frac{30}{5} = 6$$
Validation: Substitute $$x=5$$ and $$y=6$$ → Original: $$5 \cdot 6 = 30$$ ; Simplified: $$K = 30$$ ✓
4. Problem-Solving Techniques
- Visual Strategy: Use graphs to visualize the inverse relationship and identify key points.
- Error-Proofing: Always check the consistency of the product $$xy = K$$ after solving for one variable.
- Concept Reinforcement: Practice with various scenarios to understand how changes in one variable affect the other.