Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

shelovespiano

Let u=(4,0,1), v=(5,-1,0), and w=(-3,1,-2). Find the area of the triangle determined by u and v.

  • 2 years ago
  • 2 years ago

  • This Question is Closed
  1. slaaibak
    Best Response
    You've already chosen the best response.
    Medals 2

    I think the area for the parallelogram would be the length of the cross product. |u x v|

    • 2 years ago
  2. slaaibak
    Best Response
    You've already chosen the best response.
    Medals 2

    Therefore, the area of the triangle would be the half of }u x v|

    • 2 years ago
  3. shelovespiano
    Best Response
    You've already chosen the best response.
    Medals 0

    Thanks!

    • 2 years ago
  4. shelovespiano
    Best Response
    You've already chosen the best response.
    Medals 0

    Could you write it out? I'm a little confused, I guess.

    • 2 years ago
  5. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    what have you some up with in the cross product so far?

    • 2 years ago
  6. shelovespiano
    Best Response
    You've already chosen the best response.
    Medals 0

    I have (20, 0, 0) but I feel like I've done something wrong... I'm not very good with vectors.

    • 2 years ago
  7. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    \[\begin{vmatrix}X&Y&Z\\U_x&U_y&U_z\\V_x&V_y&V_z\end{vmatrix}\to X\begin{vmatrix}\\U_y&U_z\\V_y&V_z\end{vmatrix} -Y\begin{vmatrix}\\U_x&U_z\\V_x&V_z\end{vmatrix} +Z\begin{vmatrix}\\U_x&U_y\\V_x&V_y\end{vmatrix}\]

    • 2 years ago
  8. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    thats the "formal" confusion for it: me, i just do this x 4 5 x = 1 y 0 -1 y = 5 z 1 0 z = -4

    • 2 years ago
  9. shelovespiano
    Best Response
    You've already chosen the best response.
    Medals 0

    How does what you just did work?

    • 2 years ago
  10. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    so, the length of the vector <1,5,-4> its the same process as the fancy typing; but in a vertical format that I can keep track of better

    • 2 years ago
  11. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    turn the matrix on its side pretty much and expand down the first column; taking the determinant of each sub matrix along the way

    • 2 years ago
  12. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    <1,5,-4> ^2 = 1 + 25 + 16 = sqrt(42) sqrt(42)/2 = area triangle

    • 2 years ago
  13. shelovespiano
    Best Response
    You've already chosen the best response.
    Medals 0

    thank you!!

    • 2 years ago
  14. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    there are other ways to do it if you cant cross that well :)

    • 2 years ago
  15. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    but the cross bypasses any trig you might not know

    • 2 years ago
  16. shelovespiano
    Best Response
    You've already chosen the best response.
    Medals 0

    Ok. I think this works pretty well for me:P

    • 2 years ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.