# Inverse relationship between 2 variables

### The relationship between variables - Draw the correct conclusions

10 Explain a direct and inverse relationship between two variables and give an Q. - Q=20+3Q =5Q Q=20 - P=(20) P=80 - P=20+3(20) P=80 You can find an inverse relationship in mathematics in three ways. If the relationship between the variables is direct, then the dependent variable increases when you How do I Define Two Step Equations for Algebra 2?. A negative correlation means that there is an inverse relationship between two variables - when one variable decreases, the other increases. The vice versa is a .

This inverse relationship is useful when simplifying complex algebraic expressions and solving equations. Another pair of inverse mathematical operations is raising a number to an exponent "n" and taking the nth root of the number.

The square relationship is the easiest to consider.

If you square 2, you get 4, and if you take the square root of 4, you get 2. This inverse relationship is also useful to remember when solving complex equations. Functions Can Be Inverse or Direct A function is a rule that produces one, and only one, result for each number you input. The set of numbers you input is called the domain of the function, and the set of results the function produces is the range.

If the function is direct, a domain sequence of positive numbers that get larger produces a range sequence of numbers that also get larger. An inverse function behaves in a different way. When the numbers in the domain get larger, the numbers in the range get smaller. As x gets larger, f x gets closer and closer to 0. Basically, any function with the input variable in the denominator of a fraction, and only in the denominator, is an inverse function.

Two Functions Can Have an Inverse Relationship to Each Other A third example of an inverse relationship in mathematics is a pair of functions that are inverse to each other.

You get these points: This is a straight line with slope 2 and y-intercept 1. As one variable increases, the other also increases, and as one decreases, the other also decreases. In contrast, inverse variation suggests that variables change in opposite directions. As one increases, the other decreases and vice versa.

Direct Variation Consider the case of someone who is paid an hourly wage. The amount of pay varies with the number of hours worked.

This is an important component of direct variation: When one variable is 0, the other must be 0 as well. So, if two variables vary directly and one variable is multiplied by a constant, then the other variable is also multiplied by the same constant.

## Negative relationship

If one variable doubles, the other doubles; if one triples, the other triples; if one is cut in half, so is the other. In the preceding example, the equation is y 12x, with x representing the number of hours worked, y representing the pay, and 12 representing the hourly rate, the constant of proportionality.

Graphically, the relationship between two variables that vary directly is represented by a ray that begins at the point 0, 0 and extends into the first quadrant. In other words, the relationship is linear, considering only positive values. See part a of the figure on the next page. The slope of the ray depends on the value of k, the constant of proportionality.

The bigger k is, the steeper the graph, and vice versa. Inverse Variation When two variables vary inversely, one increases as the other decreases.

### Negative Correlation - Variables that Move in Opposite Direction

As one variable is multiplied by a given factor, the other variable is divided by that factor, which is, of course, equivalent to being multiplied by the reciprocal the multiplicative inverse of the factor. For example, if one variable doubles, the other is divided by two multiplied by one-half ; if one triples, the other is divided by three multiplied by one-third ; if one is multiplied by two-thirds, the other is divided by two-thirds multiplied by three-halves.

Consider a situation in which miles are traveled.

- Negative Correlation
- Variation, Direct and Inverse
- Relationship Between Variables

If traveling at an average rate of 5 miles per hour mphthe trip takes 20 hours.