Answer:
The sum of the arithmetic series is 2717.
Step-by-step explanation:
The sum of an arithmetic sequence is given by:

Where <em>k</em> is the number of terms, <em>a</em> is the initial term, and <em>x</em>_<em>k</em> is the last term.
There are 22 terms, the first term is 7, and the last term is 240. Hence, the sum is:

In conclusion, the sum of the arithmetic series is 2717.
The best answer is C) y=4.75 * cos(0.52x - 2.08) + 7.65
Unfortunately, the two only ways to solve this problem are to either graph all the options or plug in time values for x and see which agrees the most with the tide chart. Both are time-consuming, but I chose to graph each one with a graphing application.
Plugging in a few values for x confirms that C is the best function.
12pm (x=0)
y = 4.75 * cos(0 - 2.08) + 7.65
y = 5.334
2pm (x=2)
y= 6.5
4pm (x=4)
y=12.4
It is not a perfect representation, but the shape of the graph and closeness to the points given is the best of the four options provided.
<em>Look</em><em> </em><em>at</em><em> </em><em>the</em><em> </em><em>attached</em><em> </em><em>picture</em><em> </em><em>⤴</em>
<em>Hope</em><em> </em><em>it</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>u</em><em>.</em><em>.</em><em>.</em>
<em>✴</em><em>Have</em><em> </em><em>a</em><em> </em><em>great</em><em> </em><em>day</em><em>✴</em><em>✴</em>
Hi,
Your answer would be: −2x4+10x3−21x2+19x−4
Hope I could help!~ have a good day/night :]