Mini-Investigation: Pascal's Triangle and the Binomial Theorem
Objective:Understand the relationship between Pascal's Triangle, binomial coefficients, and the binomial expansion.
Introduction:
Examine the image of Pascal's Triangle provided in the applet. Notice the sum of the two numbers directly above each number.
This triangle is more than a mathematical curiosity; it reveals patterns and relationships!
Activity 1: Exploring Pascal's Triangle
1. Finding the Next Row: Add the next row to Pascal's Triangle. Each new number is the sum of the two numbers above it.
2. Edge Numbers: Observe the pattern of the numbers on the edge of the triangle. Predict the edge numbers for the next row.
3. Row Sums: Add up the numbers in each row. Look for a pattern related to powers of 2.
4. Triangle Symmetry: Determine if Pascal's Triangle is symmetrical and prove your findings.
What other patterns can be observed in the numbers in Pascal's triangle?
Activity 2: Understanding nCr (Combinations)1. Formula Familiarity: Write the nCr formula and discuss each part of the formula.2. Calculating Combinations: Use the nCr formula to calculate the numbers in a row of Pascal's Triangle. Compare with the applet.
Explain how nCr can be used to find a particular value in Pascal's triangle
The formula for . This can be used to find the values in Pascal's triangle. For example Row 2 (used for the expansion for is .
These numbers could be calculated as .
e.g
Activity 3: Connecting to the Binomial Expansion
1. Expansion Basics: Change the value of n in "Expand (a + b)^n" on the applet and observe the expansion's relation to Pascal's Triangle.2. Coefficient Connection: Identify the coefficients in the binomial expansion and their positions in Pascal's Triangle.3. Pattern Prediction: Predict the binomial expansion of (a + b)^5 and verify using the formula or the applet.
Conclusion:Reflect on how Pascal's Triangle, nCr, and the binomial expansion are related.
Discuss the patterns discovered and their implications.
Extension:-
Explore diagonal patterns in Pascal's Triangle.
- Investigate the Fibonacci sequence within Pascal's Triangle.
- Determine the number of different pathways from the top to the bottom of the triangle.
Sharing Your Findings: After completing the investigation, share and discuss your findings.
Explore other areas where these patterns might appear. Post any interesting facts or discoveries here.
Watch following video before attempting the mini-quiz questions.
Alternatively if you feel confident with the theory, look at these worked examples of exam-style questions,
Binomial expansion - Basic
https://youtu.be/6hay4gEK-y8 Binomial expansion with negative term
https://youtu.be/qkkA8xkINVo Binomial expansion past paper question
https://youtu.be/Pl5BGmxQYvs Binomial expansion past paper question - challenging version
https://youtu.be/HugZvjtv4Io
What is the coefficient of in the expansion of ?
What is the coefficient of in the expansion of ?
What is the coefficient of in the expansion of ?
What is the constant term in the expansion of ?
What is the coefficient of in the expansion of ?
Q1-11 Practice style.
Section A Q12-54 Short style exam question
Section B Q55-56 Long style exam question