Question 475817
<pre>

< x²,2> + <2,x²> = <2+x²,2+x²>
                 _______________    _______         _
&#8741;<2+x²,2+x²>&#8741; = <font face = "symbol">Ö</font>(2+x²)²+(2+x²)² = <font face = "symbol">Ö</font>2(2+x)² = |2+x|<font face = "symbol">Ö</font>2

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</pre>