4400 Higher November 2009 Paper 4 Q17
17 \[T = \frac{n(1 + e)}{(1 - e)}\]
(a) Work out the value of \(T\) when \(n = 8.6\) and \(e = 0.2\) (2)
(b) Make \(e\) the subject of the formula \(T = \dfrac{n(1 + e)}{(1 - e)}\) (5)
| Scheme | Marks |
|---|---|
| \(\dfrac{8.6 \times (1 + 0.2)}{(1 - 0.2)}\) or \(\dfrac{10.32}{0.8}\) | M1 |
| 12.9 oe | A1 |
| (2) |
Notes
M1: for correct substitution
| Scheme | Marks |
|---|---|
| \(T(1 - e) = n(1 + e)\) | M1 |
| \(T - eT = n + en\) | M1 |
| \(en + eT = T - n\) | M1 |
| \(e(n + T) = T - n\) | M1 |
| \(\dfrac{T - n}{T + n}\) | A1 |
| (5) | |
| (7 marks) |
Notes
M1: removes fractions
M1: expands brackets
M1: collects terms
M1: factorises
A1: for \(\frac{T - n}{T + n}\) oe