NOTATION,
3
It is likewise to be observed, that when a quantity is
to be multiplied by itself, or raised to any power, the
usual method of Notation is to draw a line over the
given quantity, and at the end thereof place the Expo
nent of the Power. Thus a-f ¿| 2 denotes the same as
a + b x a + b, viz. the second power (or square) of
a + b considered as one quantity: thus, also, ab -p ¿cl 3
denotes the same as ab + bc x ab + bc x ab + bc y mz.
the third power, (or cube) of the quantity ab + be.
But in expressing the powers of quantities repre
sented by single letters, the line over the top is com
monly omitted; and so a 2 comes to signify the same
as aa or a x a, and 6 3 the same as bbb pr b x, b x b:
whence also it appears that a 2 i J will signify the same
as aabbb ; and a 5 c 2 the same as aaaaacc; and so of
others.
The Note . (or a full point) and the word into, are
likewise used instead of x * or as Marks of Multipli
cation.
Thus a + b . fl + c and a 4- b into a 4- c both signify
the same thing as a ~f b x a c, namely, the product
of a -f b by a -f c.
The Sign-z-is used to signify that the quantity pre
ceding it is to be divided by the quantity ivhich comes
after it: Thus c -z~b signifies that c is to be divided by
b; and a + b -z~ a — c, that a-\-b is to be divided by
a — c.
Also the mark ) is sometimes used as a note of Divi
sion; thus, a -f b) ab, denotes that the quantity ab is
to be divided by the quantity a 4- b ; and so of others.
But the division of algebraic quantities is most com
monly expressed by writing down the divisor under the
dividend with a line between them (in the manner of
a vulgar fraction).
Thus represents the quantity
arising by dividing c by b;
and
a 4- b
a — c
denotes the
quantity arising by dividing a 4- b by a — c. Quantities
thus expressed are called algebraic fractions; whereof
jb 2