Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
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...
 one year ago
 one year 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...
 one year ago
 one year ago

This Question is Closed

beginnersmindBest ResponseYou've already chosen the best response.1
Draw e+f, and solve for the angle.
 one year ago

beginnersmindBest ResponseYou've already chosen the best response.1
Do you need another hint?
 one year ago

krystabellBest ResponseYou've already chosen the best response.0
not 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!
 one year ago

beginnersmindBest ResponseYou've already chosen the best response.1
Ok, sometimes people get stuck but don't speak up until you ask :(
 one year ago

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

beginnersmindBest ResponseYou've already chosen the best response.1
You need theta between e and f.dw:1335665267401:dw
 one year ago

krystabellBest ResponseYou've already chosen the best response.0
but then theta=e dot f what is that...
 one year ago

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

krystabellBest ResponseYou've already chosen the best response.0
dw:1335665495008:dw
 one year ago

krystabellBest ResponseYou've already chosen the best response.0
got it got it got it....
 one year ago

beginnersmindBest ResponseYou've already chosen the best response.1
ok, that saves me some drawing :)
 one year ago

krystabellBest ResponseYou've already chosen the best response.0
now 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!!! >:/
 one year ago

beginnersmindBest ResponseYou've already chosen the best response.1
I'm probably not :)
 one year ago

eliassaabBest 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
 one year ago

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

eliassaabBest ResponseYou've already chosen the best response.1
Actually for any m and n  m e  n f can be calculated and depends only on m and n and e.f
 one year ago

krystabellBest ResponseYou've already chosen the best response.0
awesome eliassaab!!!
 one year ago
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
 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.