I mainly need help on the first and second the third question is not necessary. thank you.

The rate of change in the Gross Domestic Product (GDP) of the United States is thought to be proportional to the GDP itself. In 2010, the GDP was approximately 15 trillion dollars. Write down an initial value problem that reflects the growth of the GDP. Use G(t) to represent the GDP at year t, and let { = 0 correspond to the year 2010. In 2015, the GDP was 18.2 trillion dollars. Find G(t). What does your model predict the GDP to be in 2020? Note, the GDP in 2020 was 20.94 trillion dollars. Do you think your model will provide a good estimate for the GDP in 2021? Why or why not