m …………………………. (3) (Total 5 marks) 18. The depth, metres, of the water at the end of a jetty D in the afternoon can be modelled by this formula = 5.5 + sin 30(t D A k) – where hours is the number of hours after midday, t and are constants. A k Yesterday the low tide was at 3 p.m. The depth of water at low tide was 3.5 m. Find the value of and A k. = A ……………………… = k ………………………
…………………………. m (3) (Total 5 marks) 18. The depth, D metres, of the water at the end of a jetty in the afternoon can be modelled by this formula D = 5.5 + A sin 30(t – k) where t hours is the number of hours after midday, A and k are constants. Yesterday the low tide was at 3 p.m. The depth of water at low tide was 3.5 m. Find the value of A and k. A = ……………………… k = ………………………