document.write( "Question 43603: Ok, I've got a real big problem here and i'm thoroughly overwhelmed and confused. Can someone please help. Here's the problem:\r
\n" ); document.write( "\n" ); document.write( "The formula for calculating the amount of money returned for an initial deposit money into a back account or CD (Certificate of Deposit) is given by
\n" ); document.write( "A = P(1 + r/n)^m.\r
\n" ); document.write( "\n" ); document.write( "A is the amount of return
\n" ); document.write( "P is the principal amount initially deposited
\n" ); document.write( "R is the annual interest rate (expressed as a decimal)
\n" ); document.write( "N is the compound period
\n" ); document.write( "T is the number of years\r
\n" ); document.write( "\n" ); document.write( "Suppose you deposit $10,000 for 2 years at a rate of 10%. Calculate the return (A) if the bank compounds annual (n=1).
\n" ); document.write( "Answer -\r
\n" ); document.write( "\n" ); document.write( "Show work in space. Use ^ to indicate the power.\r
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\n" ); document.write( "\n" ); document.write( "Calculate the return (A) if the bank compounds quarterly (n = 4), and carry all calculations to 7 significant figures.\r
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\n" ); document.write( "\n" ); document.write( "Show work in this space - \r
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\n" ); document.write( "\n" ); document.write( "Calculate the return (A) if the bank compounds monthly (n=12), and carry all calculations to 7 significant figures.\r
\n" ); document.write( "\n" ); document.write( "Answer -\r
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\n" ); document.write( "\n" ); document.write( "Calculate the return (A) if the bank compounds daily (n=365), and carry all calculations to 7 significant figures.\r
\n" ); document.write( "\n" ); document.write( "Answer -\r
\n" ); document.write( "\n" ); document.write( "Show work in space -\r
\n" ); document.write( "\n" ); document.write( "What observation can you make about the increase in your return as your compounding increases more frequently?\r
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\n" ); document.write( "\n" ); document.write( "If a bank compounds continuously, then the formula takes a simpler, that is A = Pe^n. Where e is a constant and equals approximately 2.7183. Calculate A with continuous compounding.\r
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\n" ); document.write( "\n" ); document.write( "Show work in space -\r
\n" ); document.write( "\n" ); document.write( "Now suppose, instead of knowing t, we know that the bank returned to us $15,000 with the bank compounding continuously. Using natural logarithms, find how long we left the money in the bank (find f).\r
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\n" ); document.write( "\n" ); document.write( "Show work in space - \r
\n" ); document.write( "\n" ); document.write( "A commonly asked question is, \"How long will it take to double my money?\" At 10% interest rate and continuous compounding, what is the answer?\r
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Algebra.Com's Answer #28609 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
A = P(1 + r/n)^m.\r
\n" ); document.write( "\n" ); document.write( "Suppose you deposit $10,000 for 2 years at a rate of 10%. Calculate the return (A) if the bank compounds annual (n=1).\r
\n" ); document.write( "\n" ); document.write( "A=10000(1+0.10/1)^2
\n" ); document.write( "A=10000*1.21= 12100\r
\n" ); document.write( "\n" ); document.write( "Calculate the return (A) if the bank compounds quarterly (n = 4), and carry all calculations to 7 significant figures. (I assume you mean for 2 years)
\n" ); document.write( "A=10000(1+0.10/4)^(4*2)
\n" ); document.write( "A=10000(1.2184029
\n" ); document.write( "A=12184.03\r
\n" ); document.write( "\n" ); document.write( "Calculate the return (A) if the bank compounds monthly (n=12), and carry all calculations to 7 significant figures. (I assume you for 2 years)
\n" ); document.write( "A=10000(1+0.10/12)^(12*2)
\n" ); document.write( "Use your caluculator.\r
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\n" ); document.write( "\n" ); document.write( "Calculate the return (A) if the bank compounds daily (n=365), and carry all calculations to 7 significant figures. (I assume you mean for two years)\r
\n" ); document.write( "\n" ); document.write( "A=10000(1+0.10/365)^(365*2)
\n" ); document.write( "Use calculator.\r
\n" ); document.write( "\n" ); document.write( "What observation can you make about the increase in your return as your compounding increases more frequently?
\n" ); document.write( "That should be obvious.\r
\n" ); document.write( "\n" ); document.write( "If a bank compounds continuously, then the formula takes a simpler, that is A = Pe^n. Where e is a constant and equals approximately 2.7183. Calculate A with continuous compounding.
\n" ); document.write( "You have to be given the rate and the number of years.\r
\n" ); document.write( "\n" ); document.write( "A=Pe^(rn)
\n" ); document.write( "A=10000(e^(0.10*?)\r
\n" ); document.write( "\n" ); document.write( "Now suppose, instead of knowing t, we know that the bank returned to us $15,000 with the bank compounding continuously. Using natural logarithms, find how long we left the money in the bank (find f).\r
\n" ); document.write( "\n" ); document.write( "15000=10000e^(0.10t)
\n" ); document.write( "1.5=e^0.10t
\n" ); document.write( "ln(1.5)=0.10t
\n" ); document.write( "0.40546511...=0.10t
\n" ); document.write( "t=4.05 years\r
\n" ); document.write( "\n" ); document.write( "\"How long will it take to double my money?\" At 10% interest rate and continuous compounding\r
\n" ); document.write( "\n" ); document.write( "2P=Pe^(0.10t)
\n" ); document.write( "2=e^(0.10t)
\n" ); document.write( "ln2=0.10t
\n" ); document.write( "0.69314718...=0.10t
\n" ); document.write( "t=6.93 years
\n" ); document.write( "This is generally call \"the rule of seven\".\r
\n" ); document.write( "\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.\r
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