i need help with solving this
a geometric sequence has a third term, a3= -48 and fourth term a4= 32. find the first term, a1 of this sequence
i'm kinda confuse as how to solve this
2007-06-05 15:13:56 · 3 answers · asked by over the air 3 in Education & Reference ➔ Homework Help
A geometric sequence is a set of numbers where the next number is multiplied by a set constant. In this case, we divide a4 by a3 to find the multiplying factor and we find it to be -2/3. To find a1, we must divide a3 by the factor twice, once to get to a2 and once to get a1:
a2 = a3/(-2/3) = 72
a1 = a2/(-2/3) = -108
2007-06-05 15:22:09 · answer #1 · answered by yeeeehaw 5 · 1⤊ 0⤋
If these are the only two "points" you have to work with, a1 can be worked out logically: (1) the difference between a3 & a4 is 80 (2) a2 would be -128 and (3) a1 would be -208
2007-06-05 15:41:01 · answer #2 · answered by David A 7 · 0⤊ 0⤋
a4 = 32
a3 = -48
a2 = 72
a1 = -108
but I think I can think of others?????????
2007-06-05 15:27:18 · answer #3 · answered by Anonymous · 0⤊ 0⤋