  # Newbie Question

Discussion in 'Questions (Windows Mobile)' started by Stevenator65, May 30, 2008.

1. Hi, this is my first post on this great site. I have started playing around with the desktop version and am trying to make a loan formula, but I must be getting the syntax wrong.

Here is what it's supposed to look like:

Payment = (Rate + (Rate / ((1 + Rate) ^ Months) * -1)) * Principal

For some reason when I enter it like that I get a syntax error. I believe that my use of negative one is the problem.

I appreciate any help.
Thanks!
Steve

2. Heve you tried to do the math step by step so that you can pinpoint the trouble bit?

3. Yes, and that's why I think the Negative one part is the problem.

This is just a calculation for a standard car loan.

Thanks for helping.

4. have you trried to wrap the negative one in parentesis as (-1)?

5. How do I step through? I press Debug, then step through, then I tried pressing F8 but it wouldn't work.

6. Trip the formula and use msgboxs to show the current result...
Some thing like this:
Code:
`Payment=(1 + RATE)* (-1) 'This should be the critic part, if you can pass this then all ok...MSGBOX(payment)Payment=(Payment+Rate) 'I don't know how you are implemeting the rate...But you should not introduce a percentage in a direct calculation...MSGBOX(payment)Payment = Payment * Principal`
If I recal correctly, from my math lessons, multiplying by a negative number is equal to dividing by that absolut number(?)
Rate SHOULD not be in percentage, but represent the ratio...

7. I figured it out. I made an error. I was supposed to subtract 1, not multiply by negative one. Here's my final code:

Sub cmdCalc_Click
Dim Prin
Dim Rate
Dim Term
Dim MonthlyRate
Dim Payment
Dim Middle
Dim bottom

Prin = txtPrin.Text
Rate = txtRate.Text / 1200
Term = txtLength.Text * 12

bottom = ((1 + Rate) ^ (Term ))
bottom = bottom - 1
middle = Rate / bottom
Payment = (Rate + middle) * Prin

lblOut.Text = Payment

Thanks for the help.

8. There's no need to "Dim" normal variables....
You can just use the without previous settings...
If you need to share a variable bettween several subs, then put them in the Global sub, like this:

Prin=""
Rate=""
Term=""
MonthlyRate=""
Payment=""
Middle=""
bottom=""

9. Thanks again Cableguy. I'm starting to like this software, and the forum is top notch.