4MA0 Foundation June 2013 Paper 1 Q21
21
Diagram NOT accurately drawn
Work out the value of \(x\).
Give your answer correct to 1 decimal place.
(3)
| Scheme | Marks |
|---|---|
| use of cos | M1 |
\(\cos(\text{“}x\text{”}) = \dfrac{8.3}{9.5}\;(= 0.87\ldots)\) or \((\text{“}x\text{”} =)\; \cos^{-1}\left(\dfrac{8.3}{9.5}\right)\) | M1 |
| 29.1 | A1 |
| (3) |
Notes
M1: cos must be selected for use in trig ratio NOT Cosine Rule
or M2 for sin and \(\dfrac{\sqrt{\text{“}21.36\text{”}}}{9.5}\) following correct Pythagoras
or M2 for tan and \(\dfrac{\sqrt{\text{“}21.36\text{”}}}{8.3}\) following correct Pythagoras
or correct Pythag and then correct use of sine or cosine rule with “21.36”
A1: for ans rounding to 29.1 (29.1103…)