Simplify $\frac{8!}{6!}$.
Specialist Mathematics · Unit 1 · Combinatorics · Permutations (ordered arrangements) and combinations (unordered selections)
Use factorial notation.
Practise this objective
AI-marked practice questions tied to QCAA mark schemes for this exact LO. Free to start.
Start free practicePractice questions for this objective
Full questions, answers and worked solutions unlock when you start a free practice session.
Consider the expression $\frac{(n+2)!}{n!}$ where $n$ is a positive integer. (a) Use factorial notation to simplify this expression. (1 mark) (b) Hence determine the value of the expression when $n = 8$. (1 mark) (c) Use your result from part (a) to solve the equation $\frac{(k+2)!}{k!} = 132$ for positive integer $k$. (1 mark)
The table below shows values of a function $f(n)$ for selected positive integers $n$. Given that $f(n) = \frac{k \cdot (3n)!}{n! \cdot (2n)!}$ for some constant $k \in \mathbb{Z}^+$, determine the value of $k$, and hence evaluate $f(8)$.
Use factorial notation to express the product $7 \times 6 \times 5 \times 4$.
Determine the value of $n$ that satisfies the equation $\frac{(n+2)!}{n!} - \frac{(n+1)!}{(n-1)!} = 56$.