A community for students. Sign up today!
Here's the question you clicked on:
 0 viewing
 2 years ago
Find II 2e3f II assuming that e & f are unit vectors such that II e +f II=sqrt(3/2).I tried using the law of cosines but not getting it...
 2 years ago
Find II 2e3f II assuming that e & f are unit vectors such that II e +f II=sqrt(3/2).I tried using the law of cosines but not getting it...

This Question is Closed

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1Draw e+f, and solve for the angle.

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1Do you need another hint?

krystabell
 2 years ago
Best ResponseYou've already chosen the best response.0not yet, doing math & watching my 3year old and 1 year old sister is interesting...makes solving problems kind of slow...i'll post if i need another hint thanks!

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1Ok, sometimes people get stuck but don't speak up until you ask :(

krystabell
 2 years ago
Best ResponseYou've already chosen the best response.0why am I finding the theta between e & e+f....theta=e dot e+f / sqrt(3/2)...

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1You need theta between e and f.dw:1335665267401:dw

krystabell
 2 years ago
Best ResponseYou've already chosen the best response.0but then theta=e dot f what is that...

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1Where is e+f on the picture? You have a triangle and you know the length of all 3 sides.

krystabell
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1335665495008:dw

krystabell
 2 years ago
Best ResponseYou've already chosen the best response.0got it got it got it....

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1ok, that saves me some drawing :)

krystabell
 2 years ago
Best ResponseYou've already chosen the best response.0now i can move on lol i hope that you aren't much younger than me, i'm very competitive but i gotta hand it to you! idk why I got stumped i tutor calc 3!!! >:/

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1I'm probably not :)

eliassaab
 2 years ago
Best ResponseYou've already chosen the best response.1\[ (e+f) . (e+f)=e.e + e.f + f.e + f.f=2 +2 e.f= \frac 32\\ e.f =\frac 1 4\\ (2e 3f).(2e3f)=4e.e  6 e.f 6 f.e +9f.f =\\ 13  12 e.f= 13 + 3=16\\  2e  3f =\sqrt{(2e 3f).(2e3f)} =\sqrt {16}=4 \] where u.v is the dot product of u and v

beginnersmind
 2 years ago
Best ResponseYou've already chosen the best response.1Wow, that's actually nicer than calculating the angle between e and f and writing them in a new coordinate system.

eliassaab
 2 years ago
Best ResponseYou've already chosen the best response.1Actually for any m and n  m e  n f can be calculated and depends only on m and n and e.f

krystabell
 2 years ago
Best ResponseYou've already chosen the best response.0awesome eliassaab!!!
Ask your own question
Ask a QuestionFind more explanations on OpenStudy
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
 Engagement 19 Mad Hatter
 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.