Find the Sum of n terms of Geometric Sequence a = 3, n = 7, and r =4

Steps to find sum of n terms of geometric sequence:

sum of n terms of geometric sequence formula:-

S_n = `a*(r^n-1)/(r-1)`

where:

• s_n is the sum of n terms
• a is first term
• n is total number of terms
• r is common ratio

Input values are:-

a = 3

n = 7

r = 4

Put values into formula

S₇ = `a*(r^n-1)/(r-1)`

S₇ = `3*(4^7-1)/(4-1)`

S₇ = 16383.0

Follow the detailed steps listed below to find the Sum of n terms of Geometric Sequence a = 3, n = 7, and r = 4 to make your calculations faster.

• The initial step is to find out the First Term of Sequence a = 3, Common Ratio r = 4 and n = 7
• Later, substitute the given values in the Sum of n terms in G.P Formula i.e. S_n = a[(r^n-1)/(r-1)] if r > 1 and r ≠ 1 or S_n = a[(1 – rⁿ)/(1 – r)] if r < 1 and r ≠ 1
• As in the given case common ratio r is greater than 1 we will use the formula Sn = a[(r^n-1)/(r-1)] and substitute given values i.e. S₆ = 3[(4^7-1)/(4-1)]
• Simplifying further we have the Sum of n terms of Geometric Sequence S6= 16383.0.

Example for Finding Sum of n terms of Geometric Sequence