Results 1 to 3 of 3

Math Help - Question about Estimating with finite Sums

  1. #1
    Newbie
    Joined
    Sep 2009
    Posts
    15

    Question about Estimating with finite Sums

    Hi guys,
    I just started Calculus 2, the topic we're on is estimating with finite sums.
    I seem to be having a hard time with this problem in my textbook

    Distance from Velocity data

    The accompanying table gives data for the velocity of a vintage sports car accelerating from 0 to 142mi/h in 36 seconds(10 thousandths of an hour).

    Time..Velocity(mph)
    0.0....0
    0.001..40
    0.002..62
    0.003..82
    0.004..96
    0.005..108
    0.006..116
    0.007..125
    0.008..132
    0.009..137
    0.01....142

    Problem A

    Use rectangles to estimate how far the car traveled during the 36 sec it took to reach 142mph

    This one I managed to solve pretty easily using using upper and lower sums.

    The shortest possible distance :
    D= 0.001(0+40+62+82+93+108+116+125+132+137)= .798 mi

    The longest possible distance:
    D=0.001(40+62+82+96+108+116+125+132+137+142)= 0.94 mi

    Problem B

    Roughly how many seconds did it take the car to reach the halfway point? About how fast was the car going?

    this is the problem I'm having. I'm not sure where to start. I thought I could use halfway point= D/2 then work from there but I'm completely unsure on where to take it from there. A hint in the right direction would be awesome, I'm not looking for someone to solve the problem but feel free anyways.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Sep 2009
    Posts
    15
    I might appear crazy for having the one and only reply to my post LOL , but I think I might have it figured out.

    What I did is took both upper and lower distance values

    0.798/0.01=0.399/t
    0.94/.01=0.47/t

    Correct me if I am wrong but I solve for T from there!
    Follow Math Help Forum on Facebook and Google+

  3. #3
    No one in Particular VonNemo19's Avatar
    Joined
    Apr 2009
    From
    Detroit, MI
    Posts
    1,823
    Quote Originally Posted by emonimous View Post
    I'm not sure where to start. I thought I could use halfway point= D/2 then work from there but I'm completely unsure on where to take it from there. A hint in the right direction would be awesome, I'm not looking for someone to solve the problem but feel free anyways.
    Yeah, use D/2. Then the sum reduces by half of the terms. Insert an unknow for the quantity youre after...

    d/2=.001(40+60+82+96+?)

    Notice the word..."roughly"...
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finite sums to approximate integrals
    Posted in the Calculus Forum
    Replies: 3
    Last Post: October 13th 2011, 11:43 PM
  2. Estimating Sums of Alternating Series help
    Posted in the Calculus Forum
    Replies: 1
    Last Post: April 12th 2010, 04:40 AM
  3. Estimating with Finite Sums
    Posted in the Calculus Forum
    Replies: 3
    Last Post: January 20th 2009, 01:36 PM
  4. need help...finite direct sums
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: November 1st 2008, 05:32 PM
  5. Estimating With Finite Sums
    Posted in the Calculus Forum
    Replies: 1
    Last Post: December 4th 2006, 07:45 PM

Search Tags


/mathhelpforum @mathhelpforum