Question

the first term in a geometric series is 64 and the common ratio is 0.75. Find the sum of the first 4 terms in a series.

Answer 1

hi

u0 = 64 with u(n+1) = un *0.75

u3 = 64 *0.75^3 = 27

sum is : 64 * ( 0.75^4 -1) / 0.75-1 = 175

manual proof : 64 + 48+36+27 = 175