Homework Help: Calculator issues?

Tags:
1. Feb 25, 2012

yumito

1. The problem statement, all variables and given/known data
To save money you put $3000 at the end of each year in an annuity that pays 6.8% compounded annually. Use the formula for the value of an annuity. The Given Formula: Code (Text): A=P[(1+(r/n)[SUP]nt[/SUP])-1] ______________ (r/n) How much would be saved at the end of six years. 2. Relevant equations The Variables: Code (Text): P=3000 R=.068 n=1 t=6 The Completed formula: Code (Text): A=3000((1+(.068/1)^(1)(6))-1) _______________________ (.068/1) When i put this exactly into http://web2.0calc.com/ (because im without a scientific calculator at the moment) 3. The attempt at a solution My Final Answer Is: A=44102.945538271292235294118 Rounded To The Nearest dollar: A=$44103
The program I Am Submitting The Answer To Says, the answer is: A=\$21352 rounded to the nearest dollar.

My question is why is my answer wrong, is it the calculator? do i have a parentheses out of place?

_____________________________________________________________________________
EDIT: fixed spelling errors and a few minor changes, none involving the math.

Last edited: Feb 25, 2012
2. Feb 25, 2012

yumito

after about an hour of crying and an hour of raging that no1 would reply i figured out the mistake it was a parentheses

3. Feb 25, 2012

Staff: Mentor

So it was the missing parents around the (1)(6) factor right?

4. Feb 26, 2012

yumito

nope, it wasn't, even tho that would have been another issue if my post was completely honest i actually multiplied them together before i put it in the calculator, the issue was the (1+(.068/1)^(1)(6)) should have been ((1+(.068/1))^((1)(6)))

5. Feb 26, 2012

yumito

in other words, add the 1 to the fraction before the exponent

6. Feb 26, 2012

checkitagain

What I do to reduce the number of parentheses for that part in the
calculator display and make it relatively easier to read is type:

((1+0.068/1)^(1*6))

7. Feb 26, 2012

yumito

well from my time spend in my programing classes i must have completely forgotten how to debug, i have become too reliant of others help and need to seriously look at the problem before asking for help. on the most basic level, there are more just remove the outter most set of parenthesis until you see the problem lol

8. Feb 26, 2012

Staff: Mentor

Why do you show division by 1 and multiplication by 1? Instead of 1 + .068/1, why not write 1.068? And instead of 1*6, why not write just 6?

9. Feb 26, 2012

checkitagain

I was emphasizing an intermediate step where it is common for some beginning
calculator users to enter a product incorrectly. I was allowing for a denominator
other than 1 and a larger product for the exponent by my example.**

For myself, I would actually enter it they way you asked about for
[i[that problem[/i], because I know that is even simpler and I can
do that in my head.

** Example:

P(1 + 0.068/12)^(12*17) is what I would type for a different example
with relatively more difficult arithmetic.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook