(696, #37) Prove Property 2 of Theorem 6 for the case n = 2

(696, #39) Prove Property 6 of Theorem 6 for the case n = 3: If a is a vector, and c and d are constants, then ( c + d ) a = ca + da.
Solution:

( c + d ) a = ( c + d ) * < a1, a2, a3 >
= < c*a1 + d*a1, c*a2 + d*a2, c*a3 + d*a3 >
= c < a1, a2, a3 > + d < a1, a2, a3 >
= ca + da

by: nl