a) Show that the points (1,3,1) ,(1,1,-1),(-1,1,1) (2,2,-1) are lying on the same plane
b) For any vector r prove that r = (r.i)i+(r.j)j+(r.k)k
c) If a*(b*c)=(a*b)*c then prove that (c*a)*b=0
i will just solve this one...
recall these properties from your text: , and for any vectors (of course, for cross-products we need 3-d vectors)
Note that
and
So, assume , then
there is pretty much one step left, you can't finish it? try.and can you please show me the answer of part b (step by step)