Homework Help: HELP easy algebra vector question please!

1. Mar 26, 2009

vorcil

1. Find a.b given the following information
|a|=3

two vectors a.b are perpendicular to eachother

b
|
|
|
|__________a

3. |a| = 3
a = squareroot of 3,

if B is a vector perpendicular to a,
dunno what to do from here,

Last edited: Mar 26, 2009
2. Mar 26, 2009

Dr.D

You want the dot product of two vectors that are perpendicular to each other?

What is the cosine of a right angle?

Does that give you any ideas?

3. Mar 26, 2009

Nabeshin

This doesn't make any sense. First you say the magnitude of the vector is 3, then you say it equals the square root of three?

Also, I see no question. (Might be the dot product as Dr.D suggests but I don't see it)

4. Mar 27, 2009

Staff: Mentor

Please don't post the same problem in two different forums. You also posted this in the Calculus and Beyond forum.

5. Mar 27, 2009

HallsofIvy

One important application of "dot product" is determining if two vectors are perpendicular. Do you remember how?