Question

Sketch the points given. Use rectangles to estimate the distance traveled by the rocket over the first 120 seconds as directed.
(a) ... using 3 subintervals of equal width and the midpoint for sample points.
http://i48.tinypic.com/65ac1e.jpg

Answer 1

I tried using the rieman sum midpoint but I keep getting it wrong!!!!

Answer 2

how are you supposed to divide 140 in to three sub intervals? got me.

Answer 3

It changed it to 120

Answer 4

i guess each has length of \(46\tfrac{2}{3}\) and you take the midpoint
so first sample point would be at \(23\tfrac{1}{3}\)

Answer 5

you just ignore the 140 I guess

Answer 6

well that makes it easier

Answer 7

so it would be 30

Answer 8

no one third of 120 is 40

Answer 9

oh crap I thought it was four intervals

Answer 10

one interval would be \([0,40]\) next would be \([40,80]\) and last would be \([80,120]\) you would sample as \(20,60,100\)

Answer 11

*sample AT

Answer 12

so it would be 40[ f(20)+f(60)+f(100)]
?

Answer 13

yes that should do it

Answer 14

@satellite73 but it talks about rectangles so for each interval do I just do the X*y?

Answer 15

It's still wrong. :(

Answer 16

yes it is just rectangles, base times height

Answer 17

is the last 140,8 gone or something?

Answer 18

40[(2*20)+(4*20)+(8*20)]

Answer 19

I don't know, but this is what I did using base times height

Answer 20

and it's still wrong

Answer 21

oh i see what you did wrong

Answer 22

the base if 40, the height is 2, 4 and 8 respectively

Answer 23

you wrote \(40[ f(20)+f(60)+f(100)]\)

Answer 24

that is correct, and \(f(20)=2,f(60)=4, f(100)=8\) so it should be
\[40(2+4+8)\]

Answer 25

OH -_- wow. thanks :P I knew I was doing something too much

Answer 26

:)