2. PASCAL’S TRIANGLE
•Can you recall the formula for the square of a
binomial?
(x+ y)2 =
How about the cube of a binomial?
(x + y)3 =
3. PASCAL’S TRIANGLE
•In his “Treatise on the Arithmetical
Triangle” of 1653, French
mathematician Blaise Pascal (1623-
1662) wrote extensively about a
triangular array of numbers for
binomial coefficients, now called
4. PASCAL’S TRIANGLE
For (x + y)o 1
For (x + y)1 1 1
For (x + y)2 1 2 1
For (x + y)3 1 3 3 1
For (x + y)4 1 4 6 4 1
5. PASCAL’S TRIANGLE
If we continue Pascal’s triangle above, we
have
For (x + y)5 1 5 10 10 5 1
Thus, we have formulas for (x+y)4 and
(x+y)5.
6. Let us look at each term of the expansion
(x+y)4=x4+4x3y+6x2y2+4xy3+y4 , as shown
below.
(x+y)4 exponent of x exponent of y
sum of the exponents
x4 4 0 4
4x3y 3 1 4
6x2y2 2 2 4
3
7. Let us look at each term of the expansion
(x+y)4=x4+4x3y+6x2y2+4xy3+y4 , as shown
below.
(x+y)4 exponent of x exponent of y
sum of the exponents
x4 4 0 4
4x3y 3 1 4
6x2y2 2 2 4
3
These observations on binomial expansion will be generalized
binomial theorem.
12. FINDING THE COEFFICIENT USING BINOMIAL
THEOREM
•If t is the exponent of b, then (t
+1)st term contains a(n-t)bt and its
coefficient is.
𝑛 𝑛 − 1 𝑛 − 2 ∙∙∙ 𝑛 − (𝑡 − 1)
𝑡 𝑡 − 1 (𝑡 − 2) ∙∙∙ 1
15. Reference:
• Aoanan, Grace O. et. al. (2018) General
Mathematics for
Senior HS, C&E Publishing, Inc.
• Garces, Ian June L. et. al. (2016) Precalculus
“Teaching
Guide for Senior High School, Commission on
Higher