GEOMETRICAL PROGRESSION D1

Find the sum of the 1st ten terms of the geometrical progression 2+4+8+16+…….

Solution

G₁ = 2, r=2, n=10

S_n = G₁(rⁿ-1)

               r-1

S₁₀ = 2(2¹⁰-1)

             2-1

S₁₀ = 2(2¹⁰-1)

              1

S₁₀ = 2(2¹⁰-1)

S₁₀ = 2(1024-1)

S₁₀ = 2(1023)

S₁₀ = 2046

Hence the sum of the 1st ten terms is 2046.

TRY THIS………………….

Find the sum of the 1st twelve terms of the geometrical progression 2+4+8+16+…….