20
Number Notations, Arithmetical Operations, and Calculators
5. a. Press the y
x key (on an HP-type calculator),
b. Press the = key (on a Tl-type calculator).
6. The desired root will be found in the lighted display.
You should use your calculator to verify that (726)* = 26.944; (8.73 x 10~
5
)* =
4.436 x 102
; (0.000000416)* = 5.294 x 10~
2 , (6.591 x 10
5
)^ = 23.054.
To find the root of a number by means of a log table, you use the logarithm
laws cited on page 14, as illustrated in the following problem.
PROBLEM:
Find the value of (2530)* = ^2530.
SOLUTION:
Use the logarithm law for roots (log A
1
"
1 = 1/n log A) to find the log of (2530)*. Then
take the antilog to find the desired value.
log 2530 = log 2.53 + log 10
3 = 0.4031 + 3 = 3.4031
log 2530 = ^^- = 0.6806
(2530)* = antilog 0.6806 = 4.7931
Sequential Operations
Throughout this chapter, we have talked as though every number we wish to
use with a calculator must be entered through the keyboard. Frequently, however, we wish to use the result of a just-performed calculation (still visible in the
lighted display) as part of the next calculation step. Your calculator is able to
handle a continuous series of calculations—including logs, powers, roots, and
reciprocals as well as the basic operations of multiplication, division, addition,
and subtraction. Each make of calculator differs somewhat in the procedure for
sequential calculations, but it is extremely important that you learn to do them
easily and efficiently. You should never have to copy down intermediate results
and then reenter them later through the keyboard in order to complete the
entire calculation. One way to minimize wasteful effort is to write down all
of the operations in a single equation before starting to do any of the calculations. We shall not always do this in the illustrative problems of this book,
because stepwise explanation of problems often is more important for our purposes than is the time saved by a maximally efficient mode of calculation. With
practice, you will learn the best balance of these factors for you in solving
problems.
Number Notations, Arithmetical Operations, and Calculators
5. a. Press the y
x key (on an HP-type calculator),
b. Press the = key (on a Tl-type calculator).
6. The desired root will be found in the lighted display.
You should use your calculator to verify that (726)* = 26.944; (8.73 x 10~
5
)* =
4.436 x 102
; (0.000000416)* = 5.294 x 10~
2 , (6.591 x 10
5
)^ = 23.054.
To find the root of a number by means of a log table, you use the logarithm
laws cited on page 14, as illustrated in the following problem.
PROBLEM:
Find the value of (2530)* = ^2530.
SOLUTION:
Use the logarithm law for roots (log A
1
"
1 = 1/n log A) to find the log of (2530)*. Then
take the antilog to find the desired value.
log 2530 = log 2.53 + log 10
3 = 0.4031 + 3 = 3.4031
log 2530 = ^^- = 0.6806
(2530)* = antilog 0.6806 = 4.7931
Sequential Operations
Throughout this chapter, we have talked as though every number we wish to
use with a calculator must be entered through the keyboard. Frequently, however, we wish to use the result of a just-performed calculation (still visible in the
lighted display) as part of the next calculation step. Your calculator is able to
handle a continuous series of calculations—including logs, powers, roots, and
reciprocals as well as the basic operations of multiplication, division, addition,
and subtraction. Each make of calculator differs somewhat in the procedure for
sequential calculations, but it is extremely important that you learn to do them
easily and efficiently. You should never have to copy down intermediate results
and then reenter them later through the keyboard in order to complete the
entire calculation. One way to minimize wasteful effort is to write down all
of the operations in a single equation before starting to do any of the calculations. We shall not always do this in the illustrative problems of this book,
because stepwise explanation of problems often is more important for our purposes than is the time saved by a maximally efficient mode of calculation. With
practice, you will learn the best balance of these factors for you in solving
problems.