GPS: MM3A2e, MM3A2f, MM3A2g

 An exponential decay function has the form y = ab x, where a>0 and 0<b<1.  The base b of an exponential decay function is called the decay factor.  The time required for a substance to fall to half its initial value is called half-life.  Exponential Decay Model When a real-life quantity decreases by a fixed percent each year (or other time period), the amount y of the quantity after t years can be modeled by the equation y= a(1-r)t, where a is the initial amount and r is the percent decrease expressed as a decimal. Note that the quantity 1-r is the decay factor.

 Graph  Steps: ◦ Make a table ◦ Plot your points ◦ Asymptote? ◦ Domain & Range X-2012 Y

 Graph  Steps: ◦ Make a table ◦ Plot your points ◦ Asymptote? ◦ Domain & Range X-2012 Y

 Graph  Steps: ◦ Make a table ◦ Plot your points ◦ Asymptote? ◦ Domain & Range X-2012 Y

 When a plant dies, it stops acquiring carbon- 14 from the atmosphere. Carbon-14 decays over time with a half-life of about 5730 years. The percent P (in decimal form) of the original amount of carbon-14 that remains in a sample after t years is given by:  About how many years after a plant dies will 60% of the carbon-14 in the plant remain?

 Try page 136: 3 & 4

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