### Orthogonality

The vectors (signals) and^{5.11}are said to be

*orthogonal*if , denoted . That is to say

*right angle*and are thus

*perpendicular*geometrically.

**Example ():**Let and , as shown in Fig.5.8. The inner product is . This shows that the vectors are

*orthogonal*. As marked in the figure, the lines intersect at a right angle and are therefore perpendicular.

**Next Section:**

The Pythagorean Theorem in N-Space

**Previous Section:**

Vector Cosine