Area = 1/2 * 10 * 4 = 20 <span>sq. inches
</span><span>B. 20 sq. inches</span>
the construction of fields of formal infinite series in several variables, generalizing the classical notion of formal Laurent series in one variable. Our discussion addresses the field operations for these series (addition, multiplication, and division), the composition, and includes an implicit function theorem.
(PDF) Formal Laurent series in several variables. Available from: https://www.researchgate.net/publication/259130653_Formal_Laurent_series_in_several_variables [accessed Oct 08 2018].
A=1x3 means 1 row and 3 columns.
B=3x4 means 3 rows and 4 columns.
AB is a compatible multiplication because A has three columns and B has 3 rows.
However, BA is not a compatible multiplication because B has 4 columns while A has only 1 row.
The general trick is if you read the row/column of the two matrices as 1-3-3-4, and the two middle ones are identical, then AB would be a compatible multiplication. On the other hand, BA would read 3-4-1-3, since 4 and 1 are not identical, so it is not a valid multiplication.
Do remember 1x3 means 1 ROW and 3 COLUMNS.
Don't know can u tell me please
