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17; 187, 2057; 22,627;whats the geometric sequence?

User Oldbam
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1 Answer

2 votes

Ok

We have our data:


17;\text{ 187; 2057; 22627}

We first find the ratio (r), and that we do dividing one of the values for the inmediatly lower value:


r=(187)/(17)\Rightarrow r=11

And we doublecheck it by doing the same with other values:


r=(2057)/(187)\Rightarrow r=11

Now that we have the ratio (r), we the add the first term (a):


a=17

So, by definition the geometric sequence will be going as follows:


a_n=a\cdot r^(n-1)

Where a_n will be the geometric sequence, a the first term, r the ratio and n the ammount of terms, so:


a_n=(17)(11)^(n-1)

Now if you want to find the 3rd value in the sequence, you just replace n and so on:


a_3=(17)(11)^(3-1)\Rightarrow a_3=2057

And the fourth:


a_4=(17)(11)^(4-1)\Rightarrow a_4=22627

Therefore, the geometric sequence is:


a_n=(17)(11)^(n-1)

User AWaddington
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