BA II plus calculator

[audia4]

I tried doing a simple question using this calculator, and it keeps giving me an error.

Question: 30 year mortgage for 75,000 with payment of 576.69. What is the interest rate.

I followed the TI manual:

2nd reset enter
30 2nd [xP/Y]N

75000 PV

576.69 +- PMT

CPT I/Y

result Error

I have no clue why it's giving me an error.

Help please.

Thank you

[Ken]

It doesn't give an error for me. Try looking up the error number in your calculator manual. I always do 2nd CLR TVM before I work any problems.

[daveliu]

how do you do:
what does d(2)=5% euqal to i(2)
with BA plus professional calculator?

[Ken]

I just do (1-d/2)^(-2)=(1+i/2)^2
Solve for i.

[.Godspeed.]

I just do (1-d/2)^(-2)=(1+i/2)^2
Solve for i.

Same. This is a trap into which I almost fell. Yes, you want to become very familiar with your calculator, and I'm not saying that you didn't already know how to do this problem by hand, but you don't want to become dependent upon the calculator to a point where you can't manually perform the basics. At first when I got my BA-II Plus and was reading Broverman's online manual on how to use it, I was like, "''', I don't have to REALLY, THOROUGHLY learn the material, including those pesky increasing/decreasing annuity formulas--my calculator can do it!" Then I worked more and more through the manual and more problems online and realized that I really did have to.

So, no, I don't know a quick way the calculator can find i(n) from a d(n) or vice versa. But if YOU know how to do it yourself, without a calculator, then you're fine.

(Sorry if this comes off as ranting, but I'm really just trying to help.)

[Ken]

I know if you work through older exams, they test more things where you have to solve for i in terms of d. I think there are still a couple problems like this although it is more rare now that we have calculators. You should know how to get from equation to equation. If you work through many problems, you will probably learn the fundamentals anyways.

[sweetiepie]

cursed calculators need to learn how to solve equations!

[Ken]

... Maybe you should brush up on your algebra.

[GreatRussian]

N

75000 PV

576.69 +- PMT

CPT I/Y

Following what you did exactly, I got an I/Y of -7.68. The negative interest rate is clearly wrong. If you insert an initial step: 2nd [P/Y] 12 2nd [QUIT],
you will get a more reasonable I/Y= 8.50