8/ Sine 50 = n/ Sine 90
8 sine 90 = n Sine 50
8 sine 90 / sine 50 = n
n = 10.4
Notice this is a geometric progression since each number multiplied by some factor equals the next number in the sequence, in this case,
![10 \times r = 5 \Rightarrow r=0.5](https://tex.z-dn.net/?f=10%20%5Ctimes%20r%20%3D%205%20%5CRightarrow%20r%3D0.5)
Then by applying the formula for sum to infinity of a geometric progression,
you would divide both sides by 6 to get your answer. i hope this helps :)
Answer:(4 x 0, 4 x ( - 1)), or 0, -4)
-5
a^2-25=0
a^2=25
take the square root of both sides
a=5, and -5