Question

Write the term to term rule of `5,-10,20,-40,80,-160`. Please help???

Answer 1

The term-to-term rule is "Multiply by `-2`"

Explanation:

If the terms had been `" "5," "10," "20," "40," "80," "160`

you would probably have been happy that each term is double the previous one!

This is a GP with a common ratio `r = 10/5 = 20/10 = 2`

The terms we actually have differ in that the signs alternative between positive and negative, This simply means that the common ratio s a negative number.

Do the same : `r = (-10)/5 =20/(10) =-2`

So the term-to-term rule is "Multiply by `-2`