direct and inverse variation
Post on 23-Feb-2016
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Direct and Inverse Variation
Investigation #1Ramp height and length vs time
Direct vs Inverse
• “y varies directly as x" means… y = kx
What does that graph look like?• “y varies inversely as x" means…
y = k/x What does that graph look like?What is k?
the constant at which the graph “changes”
1.) y varies directly with x. If y = -4 when x = 2, find y when x = -6.
2.) y varies inversely with x. If y = 40 when x = 16, find x when y = -5.
Direct, Inverse, or Neither?
• g = -7p
• v = f / -3
• d = 9 / r
What is the constant of variation (k)?
• u = 5m
• z = -0.3/r
• y = (1/3) f
Real life…
(from worksheet)• 26) The electric current I, is amperes, in a
circuit varies directly as the voltage V. When 12 volts are applied, the current is 4 amperes. What is the current when 18 volts are applied?
Exponent Rules
• Multiplication means add exponents…Why? x2 x∙ 8
• Division means subtract exponents…Why? X8/x2
• Negative exponents “switch places”…
y x∙ -8
• Power to a power: multiply exponents…Why? (x2)8
Radicals, dude
• Treat them like “like terms.”• How would you simplify “3x + 8y – 9x” ?
• Simplify 3√5 + 8 √7 – 9 √5
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