Honors Algebra 2 Section 7 1 Direct and

Honors Algebra 2 Section 7. 1 Direct and Inverse Variation

• Work with a partner and do Exploration 1 and 2 on page 359. • On exploration 1 , instead of making a scatter plot, use the calculator to make a line of best fit with x as the weights and y as the distance the spring stretches from equilibrium.

Vintage Math Direct variation-two variables are related in a way that their quotient is a constant. Constant of direct variation- the quotient of two variables that vary directly.

Inverse variation- two variables are related in a way that the product of the variables is a constant. Constant of inverse variation-the product of two variables that vary inversely

• Real-life ideas for inverse variation?

Deciding if there is direct or inverse variation! • Look at quotients and products in a table of values! Constant product? Inverse variation Constant quotient? Direct variation Neither? Neither

• Direct, inverse or neither?

• Direct, inverse or neither?

Deciding a type of variation from an equation. Change the equation so either x and y is a product or x and y is a quotient. If either of these is equal to a constant (number), you have variation!

Analyze these equations. •

• Using data to write a variation equation -Find the constant -Set the product or quotient equal to the constant -Solve for y

Real-life The time t (in hours) that it takes a group of roofers to put a new roof on a house varies inversely with the number of roofers. It takes a group of 4 roofers 9 hours to put a new roof on a house. a) Make a table of values showing the times it would take if the number of workers is 2, 6, 9 and 12. b) What happens to the time it takes as the number of workers increases?

Assignment #30 Pg. 363 #3 -29 odd