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Saturday, June 22, 2013
Tuesday, June 18, 2013
Exponential Growth / Decay (Appreciation / Depreciation) Formulas and Example
Exponential growth/appreciation per time period 't' by a percentage (or rate) 'r' and an initial amount 'a' is given by the function f, where f(t)=a*(1+r)^t. That is:
Exponential decay/depreciation per time period 't' by a percentage 'r' and an initial amount 'a' is given by the function 'f', where f(t)=a*(1-r)^t. That is:
=a(1-r)^t)
Example:
In 1967, you could by an Austin Healy 3000 Mark III sports car for $4000.00. Since then, the car has appreciated in value by 6.12% per year.
What function models the value, f, of the car t years after 1967?
Solution: a=4000, r-.0612. Thus,
=4000(1+.0612)^t&space;\Rightarrow&space;f(t)=4000(1.0612)^t)
What was the value of the car in 2004?
Solution: t=37. Thus,
=36,021.17)
In what year will the car's value appreciate to over $50,000? Explain the process you used to find the answer.
Solution:
Solve 50000=4000*(1.0612)^t
by graphing
y1=50000
y2=4000*(1.0612)^x
and find the x-value of the intersection of y1 and y2.
x=42.5 year
2009.5, or 2010 by rounding up.
Exponential decay/depreciation per time period 't' by a percentage 'r' and an initial amount 'a' is given by the function 'f', where f(t)=a*(1-r)^t. That is:
Example:
In 1967, you could by an Austin Healy 3000 Mark III sports car for $4000.00. Since then, the car has appreciated in value by 6.12% per year.
What function models the value, f, of the car t years after 1967?
Solution: a=4000, r-.0612. Thus,
What was the value of the car in 2004?
Solution: t=37. Thus,
In what year will the car's value appreciate to over $50,000? Explain the process you used to find the answer.
Solution:
Solve 50000=4000*(1.0612)^t
by graphing
y1=50000
y2=4000*(1.0612)^x
and find the x-value of the intersection of y1 and y2.
x=42.5 year
2009.5, or 2010 by rounding up.
Sunday, June 16, 2013
Simple Interest vs. Compound Interest vs Continuously Compounded Interest
Simple Interest: You get some % of the original deposit. For example, if the original deposit is $1500, and the annual interest is 10%, then every year you will earn $150 from interest.
f(x)=$1500 +150x
f(1)=1500+150
f(2)=1500+150*2, etc.
f(8)=1500+150*8=1500+1200=2700
Compound Interest: You get some % both the original deposit plus the previously earned interest per pay period. For example, if the original deposit is $1500 and the the compound interest per month is 7.75%, then you earn 7.75% of $1500 + al previously earned interest.
f(x)=1500*(1+.0775)^x
f(1)=1500*1.0775=1616.25
f(2)=1500*1.0775^2=(1500*1.0775)*1.0775
=1616.25*1.0775=1741.5, etc.
f(8)=1500*(1.0775)^8=2725.39
Continuous Compound Interest Formula:
f(x)=Initial*e^(rate*time)
f(x)=1500*e^(.0775*t)
f(8)=1500*e^(.0775*8)=2788
f(x)=$1500 +150x
f(1)=1500+150
f(2)=1500+150*2, etc.
f(8)=1500+150*8=1500+1200=2700
Compound Interest: You get some % both the original deposit plus the previously earned interest per pay period. For example, if the original deposit is $1500 and the the compound interest per month is 7.75%, then you earn 7.75% of $1500 + al previously earned interest.
f(x)=1500*(1+.0775)^x
f(1)=1500*1.0775=1616.25
f(2)=1500*1.0775^2=(1500*1.0775)*1.0775
=1616.25*1.0775=1741.5, etc.
f(8)=1500*(1.0775)^8=2725.39
Continuous Compound Interest Formula:
f(x)=Initial*e^(rate*time)
f(x)=1500*e^(.0775*t)
f(8)=1500*e^(.0775*8)=2788
Sunday, June 9, 2013
01:48:07
You will have 180 minutes to complete this exam. Answer all questions below. Feel free to use a calculator and refer to textbooks to help you complete the exam. You will need to receive a minimum score of 51/60 in order to pass, so please answer carefully and check your work. Please note: If you do not answer at least 51/60 questions correctly, you will not be able to retake an exam for this subject for 3 days. If you fail more than 1 exam for a given subject, you will not be considered for tutoring that subject. Good Luck!
Click here and choose the appropriate subject to view the Concept List. To ensure that the test loads properly and there are no formatting issues, please do not proceed unless you are using Internet Explorer 7 or greater.
Click here and choose the appropriate subject to view the Concept List. To ensure that the test loads properly and there are no formatting issues, please do not proceed unless you are using Internet Explorer 7 or greater.
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