Solving the trigonometric equation, it is found that during the first 11 years, the population size will be of 4700 in 3.62 and 7.24 years.
It is given by:
[tex]p(t) = 4096 - 1269\cos{\left(\frac{2\pi}{11}t\right)}[/tex]
It will be of 4700 when p(t) = 4700, hence:
[tex]p(t) = 4096 - 1269\cos{\left(\frac{2\pi}{11}t\right)}[/tex]
[tex]4700 = 4096 - 1269\cos{\left(\frac{2\pi}{11}t\right)}[/tex]
[tex]604 = - 1269\cos{\left(\frac{2\pi}{11}t\right)}[/tex]
[tex]\cos{\left(\frac{2\pi}{11}t\right)} = -\frac{604}{1269}[/tex]
[tex]\cos{\left(\frac{2\pi}{11}t\right)} = -0.47596532702[/tex]
[tex]\cos^{-1}{\cos{\left(\frac{2\pi}{11}t\right)}} = cos^{-1}{-0.47596532702}[/tex]
Then:
[tex]\frac{2\pi}{11}t = 2.06685766[/tex]
[tex]t = \frac{11 \times 2.06685766}{2\pi}[/tex]
[tex]t = 3.62k, k = 1, 2, ...[/tex]
Thus:
t = 3.62 x 1 = 3.62
t = 3.62 x 2 = 7.24.
The population size will be of 4700 in 3.62 and 7.24 years.
More can be learned about trigonometric equations at https://brainly.com/question/24680641