Week 2 – Geometric Sequence

This week, I have learned how to solve a geometric sequence. The difference between geometric and arithmetic is that you have addition for arithmetic and multiplication on geometric.

Vocabulary

Geometric sequence : In geometric sequence, you use the formula,

t_n=t_1r^{n-1}

t_1 is the first term and r is the common ratio.

To find the common ratio, you divide the second term from the first term.

Example:

r=\frac{t_2}{t_1}

r=\frac{6}{3}

r= 2

So, if you have t_1 as 5 and your common ratio is 2, you would have something like this.      5, 10, 20, 40, 80, 160

Now lets have a practice. 2, 4, 8, 16, 32, 64 …

Let’s find the t_8

r=2    t_1 = 2   n= 8

t_n=t_1r^{n-1}

 

t_8=2(2^{8-1})

 

t_8=2(128)

 

t_8=256

 

Its simple as that. Next week, we will look at something new because we will have a new chapter. Stay tuned

 

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