Answer:
Simple sum. The symbol Σ (sigma) is generally used to denote a sum of multiple terms. This symbol is generally accompanied by an index that varies to encompass all terms that must be considered in the sum.
First thing to do is to change the radians to degrees so it's easier to determine our angle and where it lies in the coordinate plane.

. If we sweep out a 210 degree angle, we end up in the third quadrant, with a 30 degree angle. In this quadrant, x and y are both negative, but the hypotenuse, no matter where it is, will never ever be negative. So the side across from the 30 degree reference angle is -1, and the hypotenuse is 2, so the sine of this angle, opposite over hypotenuse, is -1/2
Speed is computed by dividing total distance by total time.
Speed = Total Distance / total time
From the above formula, we can derive the formula of time and distance.
Time = Distance / Speed
Distance = Speed x time
To determine the location of a point on a graph, the first number of the ordered pair is a x-coordinate which means the first number you would look for would be the horizontal line, or the x-axis. The second number is the y-coordinate which means that you would look on the vertical line, or the y-axis. You would go on the horizontal line first, then from there go up to the y-coordinate and place your point. (I'm sorry if it's long but you can try to shorten it.)
Hope this helped!
Have a nice day!
The image below shows y = 5/3x - 9 being graphed.
Hope this helps! :)