2. The world's growing population can be modelled by an exponential equation. If we assume the world's population was approximately 4 billion in the year 1975, then the population at a time t years after 1975 can be found by the equation P = 460.019t c. Estimate the world's population when you are 30 years old. d. At what rate is the population changing at this time? 3. The height of the tides at a certain spot in Nova Scotia can be found by the equation h(t) = 5sin(0.5t + 2) + 6, where t is the time in hours (using a 24 hour clock) and h is the height in metres. What is the rate of change of height at a time of 07:00 h? 4. An apple orchard now has 60 trees planted per hectare and the average yield is 500 apples per tree. For each additional tree planted per hectare, the average yield per tree is reduced by approximately five apples. How many trees per hectare will give the largest crop of apples