Proving perpendicular vectors using Dot Product

In summary, the dot product of two perpendicular vectors is always equal to 0 because there is no overlap between them. To prove that two vectors are perpendicular, their dot product must be 0. The formula for calculating the dot product is a · b = |a||b|cosθ, where |a| and |b| are the magnitudes of the two vectors and θ is the angle between them. The dot product cannot be used to prove parallelism as it only measures angle, not direction. Other methods for proving perpendicularity include using the cross product or geometric proofs, but the dot product is the most commonly used and simplest method.
  • #1
crayzwalz
10
0

Homework Statement



2uiy8f6.jpg


Homework Equations



dot product a.b = lal.lblcostheta
vectors are perpendicular when a.b = 0

The Attempt at a Solution



OA . LA = 0
OA = OM + MA
LA = LO + OA

OA . LA = (OM+MA) . (LO + OA)
= OM.LO + OM.OA + MA.LO + MA.OAi get stuck here
 
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  • #2
Look at this image and try this, the notation is a little easier.

circlevectors.jpg


See if you can show A = (1/2)(S-R) and V = (1/2)(S+R)

Once you do that see if you can show A dot B = 0.
 

What is the dot product of two perpendicular vectors?

The dot product of two perpendicular vectors is always equal to 0. This is because the dot product measures the amount of overlap between two vectors, and since perpendicular vectors have no overlap, their dot product is 0.

How can the dot product be used to prove that two vectors are perpendicular?

If the dot product of two vectors is equal to 0, then the vectors are perpendicular. This is because the dot product is calculated by multiplying the components of the two vectors and then adding them together. If the result is 0, it means that the two vectors are at a 90 degree angle to each other, making them perpendicular.

What is the formula for calculating the dot product of two vectors?

The formula for calculating the dot product of two vectors, a and b, is a · b = |a||b|cosθ, where |a| and |b| represent the magnitudes of the two vectors and θ represents the angle between them.

Can the dot product be used to prove that two vectors are parallel?

No, the dot product cannot be used to prove that two vectors are parallel. This is because the dot product only measures the angle between two vectors, not their direction. Two vectors can have the same angle between them and still be parallel or not parallel, depending on their direction.

Are there any other methods for proving that two vectors are perpendicular besides using the dot product?

Yes, there are other methods for proving perpendicularity, such as using the cross product or geometric proofs. However, the dot product is often the easiest and most commonly used method for proving perpendicularity.

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