## mitosuki 3 years ago Please help! A ball is dropped from the top of a 1,000 foot building. The height of the ball is half its original height after each bounce. What will the height of the ball be after 12 bounces? Using complete sentences, explain the procedure taken to answer this question.

1. mitosuki

You dont have explain in sentences. I just want the height please!

2. moneybird

This is geometric sequence

3. mitosuki

Yes it is, I get the answer 0.48828125, But i dont think it is right.

4. moneybird

a = 1000 r = 1/2 n = 12 $1000 (\frac{1}{2})^{n-1}$

5. moneybird

It should be n not n-1

6. mitosuki

Ok I did that and get 0.488281125

7. moneybird

$1000 (\frac{1}{2})^{12}$

8. mitosuki

But why not n-1?

9. mitosuki

Because the formula I am given is with n-1, hmm idkk

10. moneybird

Do you mean the geometric formula that you are given or this question provides you a formula?

11. mitosuki

Well that's the only formula I am given in my lesson.. yeah the first part of ur question is right

12. moneybird

It shouldn't be n-1. You need to visualize the situation

13. mitosuki

Ok, then why don't you use -1? Because the first height wouldn't count right?

14. moneybird

|dw:1323133998962:dw|

15. mitosuki

thanks, i kinda understand now.

16. moneybird

Glad that you get help from Open Study

17. mitosuki

Thank you :)