Geometric series formula:sn=r−1t1(rn−1)
Determine the sum of the first twelve terms of the geometric series: 5 – 10 + 20 – 40 + … .
Geometric series formula: sn=r−1r⋅tn−t1
Determine the sum of the geometric series: 8 + 2 + 21 + …. + 5121 .
A tennis ball is dropped from the top of a building 15 m high. Each time the ball hits the ground, it bounces back to only 60% of its previous height. What is the total vertical distance the ball has travelled when it hits the ground for the fifth time?