Binomial Expansions!By: Khalid Al Khulaifi

8C

What is the Foil Method?The binomial expansion is done by the

foil method and in algebra the foil method is done by multiplying the binomials. The foil method is considered as rule and the expansion of foil is first – outer – inner – last.

If I was an engineer 100 years ago the binomial expansion would be more useful to me rather than using long multiplication because:

Its simpler than long multiplication which makes it easier.

straight forward, you understand easily by breaking it down and answering it step by step.

its easier to use when you have numbers with high powers.

more accurate.

Long Multiplication!

Foil Method!

Example:

The Binomial Expansion would make us think twice about using this method. It would be really hard to use big numbers in decimal places and multiplying them. And the Binomial Expansion requires to much effort , you have to keep writing the coefficients .

0.296²

= (1-0.704)(1-0.704)

= 1-0.704-0.704+0.495616

=0.087616

Example:

Foil Method!Long Multiplication!

Long multiplication would be more efficient when multiplying decimal numbers. I think it would be hard to multiply decimal numbers using the binomial expansion method without a calculator.

Example: How is the decimal

point positioned? 504.2 has 1 digit after the decimal point and 50.42 has 2 digits after the decimal point making a total of 3 digits after the decimal point.

The final answer must also have 3 digits after the decimal point.

So:504.2 × 50.42 = 25421.764

Example:

5²

= (4+1)(4+1)

=16+4+4+1

=25

THE

END!