Results 1 to 2 of 2

Math Help - Dot Products of Vectors - Please help me understand....

  1. #1
    Newbie
    Joined
    Mar 2009
    Posts
    4

    Dot Products of Vectors - Please help me understand....

    Hi there.

    I am working through a worksheet, however my knowledge of mathematical symbols is not very sound.

    Here is the problem. (P1 and P2 are Point 1 and Point 2 respectively.)
    T1 is a Tangent.

    P1 := 0 , 0 , 0 (xyz)
    P2 := 73.14 , 55.84 , 38.44
    T1 := 0.6409 , 0.6409 , 0.42

    I have to find a number from the following equation:

    Ψ = dist between points
    η = perp dist from P1 in dir of T1
    ξ = dist normal to T1

    Ψ = |P2 - P1|
    η = (P2 - P1) T1
    ξ = (Ψ - η)^0.5

    Please tell me if my findings are true.... I have no idea how to calculate these vectors!
    I understand they are dot products, but there don't seem to be any 'layman' explainations on the web.... Here's what I solved:

    Ψ = 3592.88
    η = 7.73
    ξ = 59.44

    Can anyone tell me if I'm correct? I'm 99% sure it's incorrect, as a following equation produces an error based on the square root of a negative number.
    I would be so grateful if someone could walk me through it!

    Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Mar 2009
    Posts
    4
    Right, I've done a little more digging, and Mathcad's giving me a COMPLETELY different solution, most likely the correct one.

    It's something to do with the DETERMINENT ie |x|

    What I need to know now, is how to transpose a determinent of a scalar, into an EXCEL function?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: April 5th 2011, 03:48 AM
  2. Coordinates, vectors and cross products
    Posted in the Geometry Forum
    Replies: 3
    Last Post: October 15th 2010, 11:20 AM
  3. vectors and sclalar products
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: January 17th 2010, 03:08 AM
  4. Cross products and orthogonal planes/vectors
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: May 18th 2009, 12:02 PM
  5. Dot products of vectors in three dimensions.
    Posted in the Advanced Algebra Forum
    Replies: 5
    Last Post: September 23rd 2007, 06:56 PM

Search Tags


/mathhelpforum @mathhelpforum