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krystabell
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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
 2 years ago
krystabell Group Title
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
 2 years ago

This Question is Closed

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

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

krystabell Group TitleBest 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!
 2 years ago

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

krystabell Group TitleBest 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)...
 2 years ago

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

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

beginnersmind Group TitleBest 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.
 2 years ago

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

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

krystabell Group TitleBest ResponseYou've already chosen the best response.0
thanks!!!
 2 years ago

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

krystabell Group TitleBest 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!!! >:/
 2 years ago

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

eliassaab Group TitleBest 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
 2 years ago

beginnersmind Group TitleBest 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.
 2 years ago

eliassaab Group TitleBest 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
 2 years ago

krystabell Group TitleBest ResponseYou've already chosen the best response.0
awesome eliassaab!!!
 2 years ago
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