Find the coefficient of x^2 in the expansion of (x + 4)^6.
Practice Questions
Q1
Find the coefficient of x^2 in the expansion of (x + 4)^6.
96
144
216
256
Questions & Step-by-Step Solutions
Find the coefficient of x^2 in the expansion of (x + 4)^6.
Step 1: Identify the expression to expand, which is (x + 4)^6.
Step 2: Recognize that we need to find the coefficient of x^2 in this expansion.
Step 3: Use the binomial theorem, which states that (a + b)^n = Σ (C(n, k) * a^(n-k) * b^k) for k = 0 to n.
Step 4: In our case, a = x, b = 4, and n = 6.
Step 5: We want the term where x is raised to the power of 2, which means we need k = 4 (since 6 - 2 = 4).
Step 6: Calculate the binomial coefficient C(6, 2), which is the number of ways to choose 2 items from 6. This is calculated as 6! / (2! * (6-2)!) = 15.
Step 7: Calculate 4^4, which is 4 * 4 * 4 * 4 = 256.
Step 8: Multiply the binomial coefficient by 4^4 to find the coefficient of x^2: 15 * 256 = 3840.
Binomial Expansion – The process of expanding expressions of the form (a + b)^n using the binomial theorem.
Binomial Coefficient – The coefficient C(n, k) represents the number of ways to choose k elements from a set of n elements.
Power of a Term – Understanding how to calculate the power of a term in a binomial expansion.