To find the explicit formula for the geometric sequence given (2, 8, 32, 128, 512, 2048,...), we first need to identify the first term and the common ratio.
- The first term \( a \) is \( 2 \).
- To find the common ratio \( r \), we divide the second term by the first term: \[ r = \frac{8}{2} = 4 \]
Now we can write the explicit formula for the \( n \)-th term of a geometric sequence, which is given by: \[ a_n = a \cdot r^{n-1} \] Substituting the values we found: \[ a_n = 2 \cdot 4^{n-1} \]
Now we will use this formula to find the 100th term, \( a_{100} \): \[ a_{100} = 2 \cdot 4^{100-1} = 2 \cdot 4^{99} \]
We can simplify this further. Since \( 4 = 2^2 \), we have: \[ a_{100} = 2 \cdot (2^2)^{99} = 2 \cdot 2^{198} = 2^{1 + 198} = 2^{199} \]
Now, we can calculate \( 2^{199} \). Depending on the context, you might need to give the result as a power or compute its numerical value.
The final answer for the 100th term of the sequence is: \[ a_{100} = 2^{199} \]
If you want the numerical value, \( 2^{199} \) can be calculated with a calculator or programming tool. It is a very large number, approximately \( 6.338 \times 10^{59} \).