# Sequence generation #2

• October 6th 2009, 07:27 AM
Ion
Sequence generation #2
i cant think of an equation that will generate me 2, -4, 6, -8, 10, -12, and so on

the closest ive gotten is 2*n*(-1)^n

but tat gives me opposite of what i want
• October 6th 2009, 07:34 AM
stapel
You're nearly there! Tweak the power on the negative one.... (Wink)
• October 6th 2009, 07:36 AM
Quote:

Originally Posted by Ion
i cant think of an equation that will generate me 2, -4, 6, -8, 10, -12, and so on

the closest ive gotten is 2*n*(-1)^n

but tat gives me opposite of what i want

HI

you are so close

$
2n \cdot (-1)^{n+1}
$