Question

i know i already posted this question but i am confused
Write the explicit formula that represents the geometric sequence -2, 8, -32, 128

Answer 1

Explicit formula means that it you plug in a value for x and you immediately get the answer. Therefore, we know the first term is -2, the second is 8, and so on. There is a common ratio of -4. We multiply each term by -4. Therefore, y=-4x + c. We don't know what c is yet. To find c, we plug in the first term. -2=-4(1) + c. This simplifies to 2=c so c is 2. We then add that back to the original equation. y=-4x + 2. This should be your equation

Answer 2

this is wat furuz told me and then he said it was wrong so i need the right way

Answer 3

Explicit formula for geometric sequence looks like \(a_n = a_1\cdot r^{n-1}\), right?

Answer 4

yes

Answer 5

And you already knew that \(a_1 = -2\) and \(r=-4\), therefore explicit formula is \(\boxed{a_n = -2(-4)^{n-1}}\)

Answer 6

correct

Answer 7

Well, there you go.

Answer 8

so thas my aswer an = -2(-4)^n1

Answer 9

Yeah

Answer 10

thanxs

Answer 11

No problem