5, -25, 125, -625
Please give me the equation for this sequence. thanks
2006-08-29 10:26:16 · 7 answers · asked by Anonymous in Education & Reference ➔ Homework Help
These are powers of 5, but with alternating signs.
First, if it were 5^n, then the series would be:
5, 25, 125, 625, ...
Or if it were (-5)^n then the even terms would be positive:
-5, 25, -125, 625, ...
Your series has the opposite signs, so multiply it by -1.
You could write the equation as:
f(n) = -1 * (-5)^n
or
f(n) = -(-5)^n
Double checking:
f(1) = -(-5)^1 = 5
f(2) = -(-5)^2 = -25
f(3) = -(-5)^3 = 125
f(4) = -(-5)^4 = -625
f(5) = -(-5)^5 = 3125
f(6) = -(-5)^6 = -15625
etc.
Here's the generalized equation for the nth term of this sequence:
f(n) = -(-5)^n
2006-08-29 10:31:40 · answer #1 · answered by Puzzling 7 · 0⤊ 0⤋
The nth term in this sequence is -3125.
f(1) = -(-5)^1 = 5
f(2) = -(-5)^2 = -25
f(3) = -(-5)^3 = 125
f(4) = -(-5)^4 = -625
f(5) = -(-5)^5 = 3125
f(6) = -(-5)^6 = -15625
f(n) = -(-5)^n
2006-08-29 10:31:57 · answer #2 · answered by YahooAnswers 2 · 0⤊ 0⤋
tn=5*-5^(n-1)..... the n represents what term you are looking for. For example, the third term would be tn=5*-5^(2), which equals 125.
2006-08-29 10:33:22 · answer #3 · answered by chamiqua42 1 · 0⤊ 0⤋
the nth term is -3125
the equation for this problem is f(x)= -(-5)^n
2006-08-29 10:30:53 · answer #4 · answered by thatshowiroll 3 · 0⤊ 0⤋
The formula is:
x(n) = -(-5)^n
The next term is -(-5)^5 = -(-3125) = 3125
2006-08-29 10:32:55 · answer #5 · answered by Will 4 · 0⤊ 0⤋
(-1)*(-5)^n
2006-08-29 10:37:06 · answer #6 · answered by mallika 2 · 0⤊ 0⤋
-3125
2006-08-29 10:32:15 · answer #7 · answered by Anonymous · 0⤊ 0⤋