Q. 57

Question

Prove part (a) of Theorem 10.8 for vectors in R3; that is, show that for u=u1, u2, u3 and v=v1, v2, v3, u + v = v + u 

Step-by-Step Solution

Verified
Answer

It is proven that u + v = v + u 

1Step 1: Given

Vectors u and v in R3.

2Step 2: Proof

Let us take two vectors,

u=1i+2j+3k  and v=4i+5j+6k LHS=u+v         =1i+2j+3k+4i+5j+6k         =1i+4i+(2j+5j)+(3k+6k)         =5i+7j+9kRHS=v+u         =4i+5j+6k+1i+2j+3k         =1i+4i+(2j+5j)+(3k+6k)         =5i+7j+9k

It is observed that, LHS=RHS

Hence, proved.