Page 43 - Excel for Scientists and Engineers: Numerical Methods

20 EXCEL: NUMERICAL METHODS

corresponding worksheet functions (ABS, EXP, INT, LEN, LEFT, MID AND
RIGHT, respectively). Others, such as Asc, Chr and Sqr, are spelled a little
differently (the corresponding worksheet functions are CODE, CHAR and SQRT,
respectively) or completely differently (LCase and UCase correspond to
LOWER and UPPER). These VBA functions are used in exactly the same way
that they are used in worksheet formulas; they take the same type of arguments
and return the same type of values.
Note that although Excel has three worksheet functions that return
logarithms (LN returns the natural or base-e logarithm, LOG10 returns the base-
10 logarithm, and LOG returns a logarithm to a specified base), VBA has only
one logarithmic function, Log, that returns the base-e logarithm. If you need to
work with base-10 logarithms in your VBA code, use the relationship loglo(a) =
loG(a)/ lo&( 10).
VBA does not provide a function to evaluate n, but you can calculate it in a
function by using the expression 4*Atn(l). Or, you can use the worksheet
function PI(), in the manner described in the following section.

Table 2-2. Some VBA Mathematical Functions
Abs Returns the absolute value of a number.
Atn Returns the arctangent of a number. The result is an angle
in radians.
cos Returns the cosine of an angle in radians.
EXP Returns e raised to a power.
Int Returns the integer part of a number (rounds down).
Log Returns the natural (base-e) logarithm of a number.
Rnd Returns a random number equal to or greater than 0 and
less than 1.
Sin Returns the sine of an angle in radians.
Sqr Returns the square root of a number.
Tan Returns the tangent of an angle in radians.

The above mathematical functions, except for Rnd, have the syntax
FuncfionName(argument). Rnd takes no argument, but requires the empty
parentheses.
VBA provides functions for working with text; some of the more useful ones
are listed in Table 2-3. Most of these are identical to Excel's text worksheet
functions. If you are unfamiliar with the use of text functions, see the syntax and
examples in Appendix 1.