State the common difference or ratio and determine a formula for the nth term. 5,10,20,40,... I got the common difference which is X 2. But I dont get the 2nd part.
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Originally Posted by blame_canada100 State the common difference or ratio and determine a formula for the nth term. 5,10,20,40,... I got the common difference which is X 2. But I dont get the 2nd part. The nth term of a geometric sequence with initial value a and common ratio r is given by $\displaystyle {a_n} = r \times a^{n-1}$ So, The nth term for this sequence would be given by: $\displaystyle {a_n} = 5 \times 2^{n-1}$
Originally Posted by blame_canada100 State the common difference or ratio and determine a formula for the nth term. 5,10,20,40,... I got the common difference which is X 2. But I dont get the 2nd part. Hi blame_canada100, You didn't find a common difference; you found a common ratio. $\displaystyle a_n=a_1r^{n-1}$ $\displaystyle a_n=5(2)^{n-1}$ Continue....
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