Decaying Exponential Function help!

[buggsta]

Hey guys, I'm trying to complete my webwork problems and I simply cannot figure out this problem!

A rubber ball is dropped onto a hard surface from a height of 8 feet, and it bounces up and down. At each bounce it rises to 85% of the height from which it fell.
(a) Find a formula for

, the height in inches reached by the ball on bounce

.

(b) How high will the ball bounce on the

bounce?

inches



What's inputed in the box is what I got but the website says it's wrong. I've tried so many varieties and just don't get it. Any ideas? Thanks so much in advance

 

[buggsta]

woops the answers I inputed didn't show up.

I got h(n)=(8)(.85)^n for the first one which is wrong

& I got h= 1.5749 for the second one which is also wrong lol. Sorry bout that

 

[Deleted member 4993]

Hey guys, I'm trying to complete my webwork problems and I simply cannot figure out this problem!

A rubber ball is dropped onto a hard surface from a height of 8 feet, and it bounces up and down. At each bounce it rises to 85% of the height from which it fell.
(a) Find a formula for

, the height in inches reached by the ball on bounce

.

(b) How high will the ball bounce on the

bounce?

inches



What's inputed in the box is what I got but the website says it's wrong. I've tried so many varieties and just don't get it. Any ideas? Thanks so much in advance

This is a geometric sequence

h_n = 0.85 * h_n-1

so

h_n = h₀ * (0.85)ⁿ where h₀ = 8 * 12" = 96"

Now continue...

 

[HallsofIvy]

buggsta, do you see Subhotosh Khan's point? The ball was dropped from an initial height of 8 feet but the problem asked for h in inches.

 

[buggsta]

oh wow what a stupid mistake! I get it now thank you so much! I think I was just doing math for too long and wasn't thinking clearly haha.