1. A plane takes off from an airport which is at sea level. The aircraft's altitude in metres at a time of t minutes is modelled by the equation h = 5400 ln(t + 1) a) What is the height of the plane after five minutes? b) What is the rate of climb of the plane after five minutes? Page 1 Version 1.1 Copyright 2020 learndirect Engineering mathematics - Calculus c) Using differentiation, show the curve y = h(t) has no stationary points, and hence comment on how realistic the model would be for large t