Section 2: Memory Stack, LAST X, and Data Storage 27
depends on the type of calculation (refer to examples above and below).
Because the number in the T-register remains there when the stack drops, this
number can be used as a constant in arithmetic operations.
Load the stack with a constant by keying the constant into the X-register and
pressing v three times. Use the constant by keying in your initial factor
and executing your planned series of arithmetic operations. Each time the stack
drops, a copy of the constant will be made available for your next calculation
and a new copy of the constant is reproduced in the T-register.
Example: A bacteriologist tests a certain strain of
microorganisms whose population typically
increases by 15% each day (a growth factor of
1.15). If he starts with a sample culture of 1000,
what will be the bacteria population at the end of
each day for five consecutive days?
Method: Use v to put the constant growth
factor (1.15) in the Y-, Z-, and T-registers and put
the original population (1000) in the display (X-
register). Thereafter, you get the new daily population whenever you press *.
In •2mode (press ´•2), your stacks would look like this: