Higher November 2020 Unit 1 Q16
16. Make \(y\) the subject of the following formula. [4]
\[2y = \sqrt{3 + my^2}\]| Scheme | Marks | Comments |
|---|---|---|
| Sight of \(4y^2 = 3 + my^2\) | B1 | FT until 2nd error for equivalent level of difficulty. Squaring. Allow \(2^2y^2\) or \((2y)^2\) for \(4y^2\). |
| \((4 - m)\,y^2 = 3\) OR \(4y^2 - my^2 = 3\) or equivalent | B1 | Isolating terms in \(y^2\). FT a formula with three or more terms AND with at least two terms in \(y^2\). |
| \(y^2 = 3 / (4 - m)\) OR \(y^2 = -3 / (m - 4)\) | B1 | Isolating \(y^2\). |
| \(y = \pm\sqrt{[3 / (4 - m)]}\) OR \(y = \pm\sqrt{[-3 / (m - 4)]}\) | B1 | Taking square root. Allow omission of \(\pm\). |