Inverse Variation Calculator

Calculate inverse variation relationships where xy = k (constant)

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Cannot be zero

Cannot be zero

The constant of variation

Quick Examples

Using formula:

Step-by-Step Solution

Verification

Check: x × y = k

Real-World Inverse Variation Examples

Scenario Variable 1 Variable 2 Constant
Speed & Time 60 mph 2 hours 120 miles
Workers & Days 4 workers 6 days 24 worker-days
Pressure & Volume 2 atm 10 L 20 atm·L
Gear Ratio 20 teeth 30 RPM 600
Price & Quantity $5 each 20 items $100 budget

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About Inverse Variation Calculator

What is Inverse Variation?

Inverse variation (also called inverse proportion) describes a relationship between two variables where their product is always constant. As one variable increases, the other decreases proportionally, and vice versa.

The Inverse Variation Formula

Primary Formula: xy = k

Alternate Forms:

  • y = k/x (solve for y)
  • x = k/y (solve for x)
  • k = xy (find the constant)

Where:

  • x and y are the two variables
  • k is the constant of variation (always non-zero)

How to Use This Calculator

  1. Select a calculation mode:
    • Find Constant (k): Enter x and y values
    • Find Y: Enter x and k values
    • Find X: Enter y and k values
  2. Enter your known values
  3. View the result with step-by-step solution

Real-World Examples of Inverse Variation

Scenario Variables Relationship
Speed & Time Faster speed = less travel time Speed × Time = Distance
Workers & Days More workers = fewer days to complete Workers × Days = Total Work
Pressure & Volume Higher pressure = smaller volume (Boyle's Law) P × V = k
Gear Ratios Larger gear = slower rotation Teeth × RPM = k

Understanding Inverse vs Direct Variation

Type Formula Relationship Graph
Inverse xy = k One increases, other decreases Hyperbola
Direct y = kx Both increase or decrease together Straight line

Frequently Asked Questions

How do I know if a relationship is inverse variation?

Check if the product of the two variables is constant. If xy always equals the same value k, it's inverse variation.

Can k be negative in inverse variation?

Yes, k can be negative, but it cannot be zero. A negative k means the variables have opposite signs.

What does the graph of inverse variation look like?

The graph is a hyperbola with two branches in opposite quadrants. It never crosses the x or y axis (asymptotic).

How is inverse variation used in physics?

Boyle's Law (P₁V₁ = P₂V₂) for gases is a classic example. As pressure increases, volume decreases proportionally at constant temperature.

Note: This calculator handles positive and negative values. The constant k must be non-zero for inverse variation to exist.