binomial expansions positive integer powers

Question 1

binomial expansion when the power is a positive integer. (a+b)^9

Answer 1

(a^9)+(9c1)(a^8)(b^1)+(9c2)(a^7)(b^2)+…(b^9)

Question 2

why can we use small values of x to use binomial expansions as approximations

Answer 2

if x is tiny, then higher powers of x will be really tiny so can be ignored

Question 3

what should you not forget when doing binomial expansions

Answer 3

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