# Algebra II Terms

## Get down with the lingo

### Asymptote

Closer and closer and closer…a line that a graph approaches but never touches.### Combined Variation

A relationship between three variables that combines or merges direct variation and inverse variation. Here's the general form:### Domain

"D" is for domain, where the denominator doesn't equal diddly (by that, we mean the denominator isn't zero). The domain is just all the possible*x*-values a rational function can take.

### Direct Variation

A relationship between two variables that are directly proportional; when one increases, the other does too, and vice versa. The general form looks like this guy right here, where*k*is the constant of variation:

*y*=

*kx*

### Extraneous Solution

A false solution to an equation. It makes the equation blow up because the denominator is zero.### Intercept

For all you sports nuts—think football. It's the point where a graph "takes," "seizes," or "crosses" an axis.### Inverse Variation

A relationship between two variables that are inversely proportional. In other words, as*x*increases,

*y*decreases, and vice versa. Here's what that looks like in equation form, where

*k*is the constant of proportionality:

### Joint Variation

Joint = together. It's a relationship where one variable is directly proportional to two other variables at the same time, with a constant of variation (*k*) thrown in for good measure. Here's the equation:

*y*=

*kxz*

### Rational Equation

Keep an eye out for "ratios" and an "=" sign. This is an equation involving one or more rational expressions.### Rational Expression

An expression with a polynomial in the numerator and another polynomial in the denominator. For the expression to be defined, the polynomial in the denominator must be non-zero. You know how grumpy mathematicians get about dividing by zero.### Rational Function

"Rational" = ratio. This is a function that's equal to the ratio of two polynomials.### Reciprocal

A "flipped" or inverted fraction. Watch out for the zeros in the denominator.### People who Shmooped this also Shmooped...

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