Free help with homework

Why join Brainly?

  • ask questions about your assignment
  • get answers with explanations
  • find similar questions

I think the ans shud be 12 but the ans given is 6. cant cosangle be -1 ? then the ans will be 12. see attached q.

answer is wrong, consider the unit vectors : <-1/sqrt(2), 1/sqrt(2)>, <-1, 0> and <1, 0>
they give you |a-b|^2 + |b-c|^2 | + |c-a|^2 = 9
oh ya sorry ans is 8
answer has to be 9
ya ya typing error sorry it is 9.



This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
=2(a^2+b^2+c^2-(a\cdot b+b\cdot c+ c\cdot a))

since a,b,c are unit vectors, their magnitude is 1. therefore a^2=|a|^2=1^2=1 :
=2(1+1+1-(a\,\cdot\,b+b\,\cdot\,c+ c\,\cdot\,a))
=6-2(a\,\cdot\,b+b\,\cdot\,c+ c\,\cdot\,a))

because a square is always nonegative : (a+b+c)^2\ge\,0
2 5 2
how to continue further?
i think we need to find the minimum value of that sum of dot products
il update shortly.. still working
okayyyy no probs
sir can u solve my next sum i posted ?
The Brain
  • The Brain
  • Helper
Not sure about the answer?
Learn more with Brainly!
Having trouble with your homework?
Get free help!
  • 80% of questions are answered in under 10 minutes
  • Answers come with explanations, so that you can learn
  • Answer quality is ensured by our experts