Calculate 5!5!5!.
A
In (1+x)n(1+x)^n(1+x)n, the coefficient of x2x^2x2 for rational nnn is n(n−1)2!\boxed{\displaystyle \frac{n(n-1)}{2!}}2!n(n−1).
B
(−3x)r(-3x)^r(−3x)r produces the correct alternating signs.
C
A non-terminating expansion of (a+bx)n(a+bx)^n(a+bx)n is valid only when ∣bxa∣<1\boxed{\displaystyle \left|\frac{bx}{a}\right|<1}abx<1.
D
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1.7.1 Binomial expansion Flashcards
Flashcards for AQA A Level Maths 1.7.1 Binomial expansion, covering the key formulae, methods and definitions you need to recall for Paper 1, Paper 2 and Paper 3. 20 cards, matched to the AQA A Level Maths (7357) specification. Recall questions account for roughly 50% of marks at A Level Maths, so these target the marks you can secure before the paper starts.