Q$1$ Prove the following

$($a$),({}_i-{}_i)=0$

$($b$)$ Using the definition of ${}^{}$ in term of $$ and $.$ Prove that

${}^{}{}^{?}$

$u+{}^{?}$

$u{}^{}=2g^{}$

$u($c$)(vec()*vec(A))+(vec(B)*vec())=$vec$(A)*vec(B)+$ivec$()(vec(A)$vec$(B))$