Geometric

Write the first four terms of a sequence given that a_n = 3Â·2^n-1 .

Step 1. Find the first term. To find the first term, a₁, substitute the term number, n = 1 in the formula and solve.

a₁= 3Â·2^1-1

a₁= 3

Step 2. Find the second term. To find the second term, a₂, substitute the term number, n = 2 in the formula and solve.

a₂= 3Â·2^2-1

a₂ = 6

Step 3. Find the third term.

a₃ = 3Â·2^3-1

a₃=12

Step 4. Find the fourth term.

a₄ = 3Â·2^4-1

a₄ = 24

The first four terms of the sequence are 3, 6, 12, and 24.