Maths Problem

  • Page

    of 1

    Previous Next
  • Peew971 17 Feb 2013 18:34:13 4,818 posts
    Seen 4 hours ago
    Registered 9 years ago
    If anyone can help with that, thank you very much :)
    I know I need to find the trapezium's area but can't find the length of its sides without just guessing. Any brain around to help?

  • grey_matters 17 Feb 2013 18:50:22 3,774 posts
    Seen 11 minutes ago
    Registered 8 years ago
    Let x be the longest side, y be the shorter one, and z the width.

    x + y = 30
    x + z = 24
    x = 2z (2 widths line up with the long side)

    So,
    x = 24 - z (re-arranging the second equation)

    which means:
    2z = 24 - z (because x = 2z)
    -> z = 8 (and x = 16, y = 14)

    You can probably do the rest yourself.

    Edited by grey_matters at 18:53:12 17-02-2013
  • Peew971 17 Feb 2013 19:11:54 4,818 posts
    Seen 4 hours ago
    Registered 9 years ago
    Great! I got those first 2 equations but didn't notice the long side being twice the width so I got stuck there.
    Thanks a lot :)
  • Deleted user 20 May 2013 21:21:26
    Help!

    http://i.imgur.com/0sIzcsW.png
    I'm useless at maths and I need to know how to answer these questions. It is the working I need. (not for me but I can't think of anyone else to run to!)

    Edited by mowgli at 21:21:45 20-05-2013
  • Shikasama 20 May 2013 21:22:28 6,869 posts
    Seen 2 hours ago
    Registered 6 years ago
    I didn't even know what a trapezium was.
  • Deleted user 20 May 2013 21:33:17
    Anyone?

    Wife needs to know for an exam in a couple of days and I'm fucking useless at maths :(
  • chopsen 20 May 2013 21:34:49 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
  • chopsen 20 May 2013 21:34:57 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
    Does that work?
  • chopsen 20 May 2013 21:35:42 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
    Hah. Awesomes.
  • RichieTenenbaum 20 May 2013 21:39:31 2,215 posts
    Seen 6 hours ago
    Registered 4 years ago
    6) K=-3 (2 squared is 4. Multiply by 3 to get 12. -3 to get -12)

    7) (x + 2)^2 -3 (shifted left by 2, down by 3) (it's plus 2 as you need x to be -2 to get back to zero and make y -3)

    8) x = -1
    max at -1,1
  • chopsen 20 May 2013 21:41:12 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
    Yeah. But mine's prettier.
  • RichieTenenbaum 20 May 2013 21:45:05 2,215 posts
    Seen 6 hours ago
    Registered 4 years ago
    It is.

    MUCH.
  • RichieTenenbaum 20 May 2013 21:45:58 2,215 posts
    Seen 6 hours ago
    Registered 4 years ago
    So, can we just type laTex into this forum?
  • X201 20 May 2013 21:48:15 15,520 posts
    Seen 11 minutes ago
    Registered 9 years ago
    RichieTenenbaum wrote:
    So, can we just type laTex into this forum?
    You've never used the search function on here have you?
  • chopsen 20 May 2013 21:48:22 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
    I went via this website, that coverts latex to a linkable gif:

    http://www.texify.com/links.php

    I was tempted to just paste some latex and see what happens, but I thought that might be overestimating poor old craigy
  • chopsen 20 May 2013 21:48:41 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
    \[\sum\limits_{i = 1}^n {X_i^2} \]

    edit: no

    Edited by Chopsen at 21:48:52 20-05-2013
  • mrpon 20 May 2013 21:51:48 28,997 posts
    Seen 3 hours ago
    Registered 8 years ago
    RichieTenenbaum wrote:
    So, can we just type laTex into this forum?
    Afraid not, google: "mwnin laTex" for the syntax.

    Give yourself 5 or gig, you're worth it.

  • Deleted user 20 May 2013 21:51:56
    Genuine thanks, she says it helps a lot (looks like fucking alien talk to me). She doesn't know how you got the answer for 8 though?
  • chopsen 20 May 2013 21:57:12 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
    at x = -1, the (x+1)^2 is equal to zero. All other values for x are going to be symmetrical around this. Raising something to the power of 2 "removes" the sign.

    So the axis of symmetry is x= -1.

    edit: why do I care?

    Edited by Chopsen at 22:07:32 20-05-2013
  • speedofthepuma 20 May 2013 22:01:47 13,293 posts
    Seen 58 minutes ago
    Registered 9 years ago
    I used to know all this. How the hell does it stick in your stupid brain? You must be horribly deficient in some other way Chopsen.

    I lurk. If I've spoken to you, I'm either impassioned, or drunk.

  • chopsen 20 May 2013 22:04:06 16,087 posts
    Seen 6 hours ago
    Registered 9 years ago
    It's only because I am actually doing some maths part time at the moment. I generally can't remember anything from more than a couple of weeks ago unless it's written down otherwise.
  • RichieTenenbaum 20 May 2013 22:05:48 2,215 posts
    Seen 6 hours ago
    Registered 4 years ago
    You need to edit a sign there, Choppo
  • RichieTenenbaum 20 May 2013 22:09:46 2,215 posts
    Seen 6 hours ago
    Registered 4 years ago
    A better way to explain 8

    x^2 is symmetrical around 0

    (x+1)^2 must be symmetrical around -1. This makes the bracket 0.
    When x is -1.

    Then y = 1 + (-1+1)^2 = 1 + (0)^2 = 1
  • Deleted user 21 May 2013 08:15:49
    Thanks again, both. She was pulling her hair out and is now able to move on.
  • Alastair 21 May 2013 08:36:14 15,886 posts
    Seen 16 minutes ago
    Registered 13 years ago
    I used to just about understand this sort of thing - did Maths A-level but failed it. :(

    I managed to work out 6 in my head. 7 I could have done on paper, 8 I would have struggled with.
  • robkilpatrick 21 May 2013 13:52:10 2 posts
    Seen 1 year ago
    Registered 1 year ago
    It take so much time to help you out
  • Page

    of 1

    Previous Next
Log in or register to reply