Heath Algebra 1 McDougal Littell JoAnn Evans Math 8H Heath 12.5 Rational Functions

A function in the form of is called a rational function. In today’s lesson you’ll study rational functions whose numerators and denominators are first-degree polynomials. Using long division, you will transform functions from to

The graphs of the functions today will all be You’ve worked with hyperbolas before in Lesson 11-1 in the Glencoe book. The graph shown here is an inverse variation graph from that lesson.

The graph of the rational function is a hyperbola whose center is. The vertical and horizontal lines through the center of the hyperbola are called the asymptotes. The asymptotes intersect at the point (h, k).

x The asymptotes intersect at the point (0, 0). In this case the asymptotes are the x- and y-axes. When h and k have values other than 0, the hyperbola will shift vertically and horizontally. The k shifts the hyperbola vertically. Positive = up Negative = down

x x Hyperbola in red: When the value of k changes, watch for the vertical shift that takes place.

When h has a value other than 0, the hyperbola will shift horizontally. The value of h will cause the graph to shift horizontally. The graph will shift horizontally the number that x must equal so that the expression in the denominator is equal to ZERO.

x x Hyperbola in red: When the value of h changes, watch for the horizontal shift that takes place.

x x k will cause the graph to shift 3 spaces UP h will cause the graph to shift 2 spaces to the RIGHT k will cause the graph to shift 2 spaces DOWN h will cause the graph to shift 1 spaces to the LEFT

Find the center of a hyperbola and the asymptotes. The center is the coordinate point The x-value will be the value x must be so that the expression x – h is equal to zero. The y-value is k.

Asymptotes are the vertical and horizontal lines that pass through the center of the hyperbola. The equation of the vertical line (asymptote) passing through the center will be the x-value of the center. The equation of the horizontal line (asymptote) passing through the center will be the y-value of the center. x The center of this hyperbola is the point (3, 1). What is the equation of the vertical asymptote? What is the equation of the horizontal asymptote?

Find the center and asymptotes of the hyperbola.

Graph a Rational Function: Step 1: Find the center of the hyperbola and lightly draw the asymptotes as dashed lines. x Step 2: Make a table of values. Choose values on both sides of the center. x f(x) Step 3: Graph both sides

Graph a Rational Function: Step 1: Find the center of the hyperbola and lightly draw the asymptotes as dashed lines. x Step 2: Make a table of values. Choose values on both sides of the center. x f(x) Step 3: Graph both sides

Using Polynomial Long Division First… This function is not in the correct form yet. Divide the numerator by the denominator. Put in parentheses and subtract. Remember to put the remainder over the divisor and add it to the quotient. Use the commutative property of addition to put the k second, then graph.

Graph a Rational Function: Step 1: Find the center of the hyperbola and lightly draw the asymptotes as dashed lines. x Step 2: Make a table of values. This time, try choosing values on just one side of the center Step 3: Make symmetrical points on the other side of the center, then graph the other part of the hyperbola. x-201 f(x)2 In relation to the center, this point is 1 right, 3 down. Reverse those directions to locate the symmetrical point. Go 1 LEFT and 3 UP to get to the symmetrical point

Using Polynomial Long Division First… This function is not in the correct form yet. Divide the numerator by the denominator. Put in parentheses and subtract. Remember to put the remainder over the divisor and add it to the quotient. Use the commutative property of addition to put the k second, then graph.

Graph a Rational Function: Step 1: Find the center of the hyperbola and lightly draw the asymptotes as dashed lines. x Step 2: Make a table of values. This time, try choosing values on just one side of the center Step 3: Make symmetrical points on the other side of the center, then graph the other part of the hyperbola. x-3-20 f(x)