< x²,2> + <2,x²> = <2+x²,2+x²> _______________ _______ _ ∥<2+x²,2+x²>∥ = Ö(2+x²)²+(2+x²)² = Ö2(2+x)² = |2+x|Ö2 Let's get the dot product of <4,2,3> and <2,-1,-2> <4,2,3>•<2,-1,-2> = (4)(2)+(2)(-1)+(3)(-2) = 8-2-6 = 0 So they are orthogonal (perpendicular). Edwin