**Question 4**

(a) By how much is the sum of 32/3 and 21/5**less than** 7?

(b) The height, h m, of a dock above sea level is given by h = 6 + 4 cos (15p)o,

0 < p < 6. Find: the value of h when p = 4; correct to **two** significant figures, the value of p when h = 9 m.

### Observation

The Chief Examiner reported that this question was attempted by majority of the candidates and they performed well in it.

In part (a), candidates were reported to have correctly subtracted the sum of 3 and 2 from 7 to obtain 7 – (+ ) = 7 - = 1.

In part (b)(i), majority were reported to have substituted 4 for p in the equation to obtain h = 6 + 4 cos(15(4))o = 6 + 4 cos 60o = 8 m. In part (b)(ii) candidates were expected to substitute 9 for h in the equation and solve for p. This gave

9 = 6 + 4 cos (15p)o. Therefore, p = = 2.8, correct to 2 significant figures.