The increase in carbon dioxide (CO $_{2}$ ) in the atmosphere is a major cause of global warming. Using data obtained by Charles David Keeling, professor at Scripps Institution of Oceanography, the average amount of $\mathrm{CO}_{2}$ in the atmosphere from 1958 through 2013 is approximated by
$$A(t)=0.012414 t^{2}+0.7485 t+313.9 \quad(1 \leq t \leq 58)$$
where $A(t)$ is measured in parts per million volume (ppmv) and $t$ in years, with $t=1$ corresponding to 1958 .
a. What can you say about the rate of change of the average amount of atmospheric $\mathrm{CO}_{2}$ from 1958 through 2013?
b. What can you say about the rate of change of the rate of change of the average amount of atmospheric $\mathrm{CO}_{2}$ from 1958 through $2013 ?$