Question

What’s the formula to -1/2,-3/10,-9/50,-27/250,....

Answer 1

The formula is ⇒
`(-1)/(2)((3)/(5))^(n-1)`

Explanation:

∵ The sequence is -1/2 , -3/10 , -9/50 , -27/250

∵ (-3/10) ÷ (-1/2) = 3/5

∵ (-9/50) ÷ (-3/10) = 3/5

∴ It is a geometric sequence

∴ The formula is Tn = ar^(n - 1)

Where a is the first term , r is the constant ratio between each two consecutive terms and n is the position of the number

∴ Tn = -1/2 ( 3/5)^(n - 1)

∴
`Tn= (-1)/(2)((3)/(5))^(n-1)`