# Thread: I keep getting it wrong! help!

1. ## I keep getting it wrong! help!

Estimate the area under the graph of f(x) = 2
 x
from x = 0 to x = 4
using four approximating rectangles and right endpoints. (Round your answers to four decimal places.)

2. ## Re: I keep getting it wrong! help!

We would be glad to help you, but we can't see where you are going wrong on this if you do not show your work.

3. ## Re: I keep getting it wrong! help!

Originally Posted by brendasants
Estimate the area under the graph of f(x) = 2
 x
from x = 0 to x = 4
using four approximating rectangles and right endpoints. (Round your answers to four decimal places.)
Is the function $f(x)=2\sqrt{x}$ or is it something else?

4. ## Re: I keep getting it wrong! help!

Originally Posted by Plato
Is the function $f(x)=2\sqrt{x}$ or is it something else?
yes that is the function.

This is what I have done so far...
a)
split up f(x) into the intervals [0, 1], [1, 2], [2, 3], [3, 4], and used right endpoints, 1, 2, 3, 4 as the heights of the rectangles.
A ≈ 1*2√1 + 1*2√2 + 1*2√3 + 1*2√4
= 6 + 2√2 + 2√3
≈ 12.293

b)
A ≈ 1*2√0 + 1*2√1 + 1*2√2 + 1*2√3
= 2 + 2√2 + 2√3
≈ 8.293

My online hw keeps marking these answers wrong. What am I doing wrong?

5. ## Re: I keep getting it wrong! help!

The only thing I can think of is your assignment says FOUR decimal places, not three.

6. ## Re: I keep getting it wrong! help!

Originally Posted by Deveno
The only thing I can think of is your assignment says FOUR decimal places, not three.
wow I feel so dumb... that was the problem lol