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Determine if its a growth or decay.Then find the percent increase of decrease....

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animalover4546 | Student, Undergraduate | (Level 2) Honors

Posted May 23, 2012 at 1:09 AM via web

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Determine if its a growth or decay.Then find the percent increase of decrease.

1.y=16(.25)^x

2.y=0.8(1.28)^x

3.y=17(1/5)^x''.

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hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted May 23, 2012 at 2:05 AM (Answer #1)

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y= 16(0.25)^x

The exponential equation represents an exponential decay because the rate of decay is 0.25 which is less than 1.

The general form equation is:

y(x)= a(1-r)^x such that r is the decay percent.

Comparing two equation we have 1-r = 0.25

==> r= 1-0.25 = 0.75 = 75%

Then, the decay percent is 75%.

 

2. y= 0.8(1.8)^x

The equation represents exponential growth because the growth factor is greater than 1.

==> 1+r = 1.8

==> r= 0.8 = 80%

Then, the growth percent is 80%

 

3. y= 17(1/5)^x

The equation represents exponential decay because 1/5 is less than 1.

==> 1-r = 1/5

==> r= 1- 1/5 = 4/5 = 0.8= 80%

Then, the decay percent is 80%

 

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