Higher June 2025 Paper 4 Q15
15 \(y\) is inversely proportional to the square of \(x\).
\(y = 5\) when \(x = 6\).
Find a formula linking \(x\) and \(y\). [3]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| \(y = \frac{180}{x^2}\) oe | 3 | M1 for \(y = \frac{k}{x^2}\) oe B1 for [\(k =\)] 180 If 0 or 1 scored instead SC2 for answer \(y \propto \frac{180}{x^2}\) or if 0 scored instead SC1 for \(y \propto \frac{1}{x^2}\) | equivalents include \(5 = \frac{k}{6^2}\) and \(yx^2 = k\) |