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Direct Variation. Direct Variation. Direct Variation. When one thing gets larger, the other gets larger. Direct Variation. When one thing gets larger, the other gets larger. For Example:. Direct Variation. When one thing gets larger, the other gets larger. For Example:
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Direct Variation • When one thing gets larger, the other gets larger.
Direct Variation • When one thing gets larger, the other gets larger. • For Example:
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains.
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains. • When the amount of food Ando eats goes up, the amount of weight he gains goes up.
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains. • When the amount of food Ando eats goes up, the amount of weight he gains goes up. • As an equation it would look like this:
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains. • When the amount of food Ando eats goes up, the amount of weight he gains goes up. • As an equation it would look like this: • W is Ando’s weight.
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains. • When the amount of food Ando eats goes up, the amount of weight he gains goes up. • As an equation it would look like this: • W is Ando’s weight. • E is the amount Ando eats.
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains. • When the amount of food Ando eats goes up, the amount of weight he gains goes up. • As an equation it would look like this: • W is Ando’s weight. • E is the amount Ando eats. • K is ALWAYS the constant amount that he gains.
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains. • When the amount of food Ando eats goes up, the amount of weight he gains goes up. • As an equation it would look like this: • W is Ando’s weight. • E is the amount Ando eats. • K is ALWAYS the constant amount that he gains. • K is called the “constant of variation”.
Direct Variation • When one thing gets larger, the other gets larger. • For Example: • The more food Ando eats, the more weight he gains. • When the amount of food Ando eats goes up, the amount of weight he gains goes up. • As an equation it would look like this: • W is Ando’s weight. • E is the amount Ando eats. • K is ALWAYS the constant amount that he gains. • K is called the “constant of variation”. • W = KE
Direct Variation • Write a direct variation equation for the following:
Direct Variation • Write a direct variation equation for the following: • The cost of postage has a constant price of 30 cents per ounce.
Direct Variation • Write a direct variation equation for the following: • The cost of postage has a constant price of 30 cents per ounce. • The distance traveled has a constant speed of 30 miles per hour.
Direct Variation • Write a direct variation equation for the following: • The cost of postage has a constant price of 30 cents per ounce. • The distance traveled has a constant speed of 30 miles per hour. • The points scored has a constant amount of 6 per touchdown.
Direct Variation • Write a direct variation equation for the following: • The cost of postage has a constant price of 30 cents per ounce. • The distance traveled has a constant speed of 30 miles per hour. • The points scored has a constant amount of 6 per touchdown. • What is the DEPENDENT and INDEPENDENT variable in each equation?
Direct Variation • Write a direct variation equation for the following: • The cost of postage has a constant price of 30 cents per ounce. • The distance traveled has a constant speed of 30 miles per hour. • The points scored has a constant amount of 6 per touchdown. • What is the DEPENDENT and INDEPENDENT variable in each equation? • What variable represents dependent and what variable represents independent in general?
Direct Variation: • What sort of standard equation rule can you make for direct variations?
Direct Variation: • Manipulating equations:
Direct Variation: • Manipulating equations: • Show me two other ways to write the equation y = kx
Direct Variation • Using the information given:
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point:
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5)
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx • Put in the information you know:
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx • Put in the information you know: • 5 = k(1)
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx • Put in the information you know: • 5 = k(1) • Solve for k.
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx • Put in the information you know: • 5 = k(1) • Solve for k. • k(1) = 5
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx • Put in the information you know: • 5 = k(1) • Solve for k. • k(1) = 5 • k = 5/1
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx • Put in the information you know: • 5 = k(1) • Solve for k. • k(1) = 5 • k = 5/1 k = 5
Direct Variation • Using the information given: • Write a direct variation equation that includes the given point: • (1,5) • The general equation is y = kx • Put in the information you know: • 5 = k(1) • Solve for k. • k(1) = 5 • k = 5/1 k = 5 y = 5x
Direct Variation • How else could we have solved for k?
Direct Variation • How else could we have solved for k? • Write an equation of direct variation that includes the given point:
Direct Variation • How else could we have solved for k? • Write an equation of direct variation that includes the given point: • (6,3)