In 2012, the world population was 7.052 billion. The birth rate had stabilized to 135 million per year and is projected to remain constant. The death rate is projected to increase from 56 million per year in 2012 to 80 million per year in 2040 and to continue increasing at the same rate.1 (a) Assuming the death rate increases linearly with time, write a differential equation for P(t), the world population in billions t years from 2012. Round the coefficient to six decimal places.