Question

Mohamed and Li Jing were asked to find an explicit formula for the sequence -5\,,-25\,,-125\,,-625,...−5,−25,−125,−625,...Minus, 5, comma, minus, 25, comma, minus, 125, comma, minus, 625, comma, point, point, point. Mohamed said the formula is g(n)=-5\cdot5^{\large{n}}g(n)=−5⋅5 n g, left parenthesis, n, right parenthesis, equals, minus, 5, dot, 5, start superscript, n, end superscript, and Li Jing said the formula is g(n)=-5\cdot5^{\large{n-1}}g(n)=−5⋅5 n−1 g, left parenthesis, n, right parenthesis, equals, minus, 5, dot, 5, start superscript, n, minus, 1, end superscript. Which one of them is right? Choose 1 answer: Choose 1 answer:

Answer 1

Answer:

Li Jing

Step-by-step explanation:

Given the sequence:

-5,-25,-125,-625,...

Mohamed's Formula is given as: $g(n)=-5\cdot5^{\large{n}}$

Using Mohamed's formula:

$When\: n=1,g(n)=-5\cdot5^{\large{n}}=-5\cdot5^{1}=-25\\When\: n=2,g(n)=-5\cdot5^{\large{n}}=-5\cdot5^{2}=-125$

Li Jing's Formula is given as: $g(n)=-5\cdot5^{\large{n-1}}$

Using Mohamed's formula:

$When\: n=1,g(n)=-5\cdot5^{\large{n-1}}=-5\cdot5^{1-1}=-5\\When\: n=2,g(n)=-5\cdot5^{\large{n-1}}=-5\cdot5^{\large{2-1}}=-25$

We can see that Li Jing's Formula produces the gien sequence.

Li Jing is Right.