4400 Higher November 2009 Paper 3 Q21
21 \(t\) is proportional to the square root of \(d\).
\(t = 12\) when \(d = 4\)
(a) Find a formula for \(t\) in terms of \(d\). (3)
(b) Calculate the value of \(t\) when \(d = 9\) (2)
| Scheme | Marks |
|---|---|
| \(t = k\sqrt{d}\) | M1 |
\(12 = k\sqrt{4}\) \(k = 6\) | M1 |
| \(t = 6\sqrt{d}\) | A1 |
| (3) |
Notes
A1: Must make \(t\) the subject
| Scheme | Marks |
|---|---|
| “6” × \(\sqrt{9}\) | M1ft |
| 18 | A1 ft |
| (2) | |
| (5 marks) |