I guess you are asking to find the sum of the first 8 terms. If so, then:
Sum = a₁(1-rⁿ)/(1-r), where a₁ is the 1st term, r=common ratio and n=number of terms:
the 1st term a₁ =3
common ratio r = - 2 (since -6/3 = - 2, and 12/-6 = - 2, etc.)
Sum = 3[(1- (-2)⁸]/(1-2) = 3(1- 256)/(1/2)
Sum = -1530
The length of arc AB is 9.12 mm:
We first calculate for the radius r of the circle using the equation
r = c/(2 sin[theta/2])
where c is the length of chord AB that is given as 9 millimeters
angle given is 32 degrees
To convert theta 32 degrees into radians:
32 degrees * (pi/180) = 32 degrees * (3.14/180) = 0.5583 radians
We now substitute the values into the equation to find the radius r:
r = 9/(2 sin[0.5583/2])
r = 16.33 mm
.
We can finally solve for the length s of arc:
s = r theta = 16.33 * 0.5583 = 9.12 mm
G (x) = -11/4 ...
that's your answer
