4MA0 Foundation January 2017 Paper 2R Q21
21
Diagram NOT accurately drawn
Work out the value of \(x\).
Give your answer correct to 3 significant figures.
(3)
| Scheme | Marks |
|---|---|
| \(12.8^2 - 9.7^2\) or 163.84 − 94.09 or 69.75 | M1 |
| \(\sqrt{12.8^2 - 9.7^2}\) | M1dep |
| 8.35 | A1 |
| (3) | |
| (3 marks) |
Notes
M1: For squaring and subtracting
[\(a = \cos^{-1}\left(\dfrac{9.7}{12.8}\right)\) (= 40.7…) and \(\sin 40.7\ldots = \dfrac{x}{12.8}\) or \(\tan 40.7\ldots = \dfrac{x}{9.7}\)]
M1dep: For square root
[\(x = 12.8 \sin 40.7\ldots\) or \(x = 9.7 \tan 40.7\ldots\)]
A1: Allow 8.35 - 8.352