### Number 202 of a series

Something for the math people. The plane shown above is defined by:

### z = 5x +4y

What is the unit vector perpendicular to the plane? Give the answer in terms of

### (ai, bj, ck)

Where i, j, and k are unit vectors for the x, y, and z axes. Submit your answer in the comments section below.

Did you mean z = 5x +4y ?

Steve, you are right. Remind me not to compose any math questions after a couple of glasses of wine.

A normal vector is 5i + 4j – k. To get the unit vector, divide by the norm, i.e., sqrt(5^2 + 4^2 + 1) = sqrt(42).

BTW, who is this Steve of which you speak? I am Elmo.