TI 85 Information

The following equation (revised Aug. 2005) will provide the TI-85 (and TI-86) with financial capabilities.  When it is entered, it will be stored for future use.  (The zero coefficient of PMT forces the calculator to display the variables in a different order.)

• FINAN=-PV+0*PMT-FV-((1+.01*IY/PY)^N-1)(PV+100*PMT(PY+.01*DUE*IY)/IY)

Financial Variables

N, number of periods
IY, rate of interest per year

PY, periods per year
PMT, payment per period
PV, present value
FV, future value

Conventions

Payments which increase the balance are positive numbers.
Payments which decrease the balance are negative numbers.
Future values are withdrawals, usually entered as negative numbers.

Floating Decimal

Press 2nd MODE, place the cursor on Float, press ENTER, press CLEAR.

Financial Mode

Press 2nd SOLVER CLEAR, press the F key corresponding to FINAN, then press ENTER.

Clearing Financial Data

Move the cursor to the appropriate variable and enter zero.

Beginning Annuities

Move the cursor to DUE and enter a value of 1.

Entering Financial Data

Move the cursor to the appropriate variable and enter the value.

Computing Values

Move the cursor to the appropriate variable and press F5 (to solve).

Example:

Tom's account begins with $500, and earns 6% per year, compounded monthly. He deposits an additional $50 at the end of each month. What will the balance be at the end of one year?

The variables are:

N = 12

I = 6/12 = 0.5

PMT = 50 increasing

PV = 500

FV = ???

To begin, the keystrokes are:

2nd SOLVER CLEAR

Press the F key corresponding to the program FINAN

ENTER

Then for each variable, enter the following value and press ENTER:

exp = 0
PV = 500
PMT = 50
FV =
IY = 6

PY = 12
N = 12
DUE = 0
bound = {-1E99, 1E99}

Then move the cursor to FV, and press F5.

The answer is $1,147.62, rounded to the nearest cent.