Easy -1.2 This is a straightforward application of the binomial theorem with a small positive integer power (n=4) and simple coefficients. It requires only direct recall of the binomial expansion formula and basic arithmetic to simplify coefficients like C(4,2)×(1/2)². No problem-solving or conceptual understanding beyond the formula itself is needed, making it easier than average but not trivial since it requires careful calculation of four terms.
B3 for 4 terms correct, or B2 for 3 terms correct or for all correct but unsimplified (may be at an earlier stage, but factorial or "C" notation must be expanded/worked out) or B1 for \(1, 4, 6, 4, 1\) soi or for \(1 + ... + \frac{1}{16}x^4\) [must have at least one other term]
$1 + 2x + \frac{3}{2}x^2 + \frac{1}{4}x^3 + \frac{1}{16}x^4$ o.e. (must be simplified) isw | 4 | B3 for 4 terms correct, or B2 for 3 terms correct or for all correct but unsimplified (may be at an earlier stage, but factorial or "C" notation must be expanded/worked out) or B1 for $1, 4, 6, 4, 1$ soi or for $1 + ... + \frac{1}{16}x^4$ [must have at least one other term]