All Precalculus Resources
Example Questions
Example Question #11 : Determine If Two Vectors Are Parallel Or Perpendicular
Which of the following pairs of vectors are parallel?
For two vectors, and to be parallel, , for some real number .
Recall that for a vector, .
The correct answer here is
This is the correct answer because .
Example Question #12 : Determine If Two Vectors Are Parallel Or Perpendicular
Which of the following pairs of vectors are parallel?
For two vectors, and to be parallel, , for some real number .
Recall that for a vector, .
The correct answer here is
.
Using the formula we have our to be .
Applying this we find the vector that is parallel.
Example Question #11 : Determine If Two Vectors Are Parallel Or Perpendicular
Which pair of vectors represents two parallel vectors?
Two vectors are parallel if their cross product is . This is the same thing as saying that the matrix consisting of both vectors has determinant zero.
This is only true for the correct answer.
In essence each vector is a scalar multiple of the other.
Example Question #11 : Parallel And Perpendicular Vectors In Two Dimensions
Which relationship best describes the vectors and ?
the same direction, but different magnitudes
perpendicular
neither parallel nor perpendicular
more information needed
parallel
perpendicular
We can discover that these vectors are perpendicular by finding the dot product:
A dot product of zero for two non zero vectors means that they are perpedicular vectors.
Example Question #15 : Matrices And Vectors
Which relationship best describes the two vectors and ?
both parallel and perpendicular
neither parallel nor perpendicular
parallel
perpendicular
more information is needed
parallel
To show that these are parallel, we have to find their magnitudes using the Pythagorean Theorem:
To multiply , multiply the numbers within the radicals first, then take the square root:
Now we have to find the dot product and compare it to the product of these two magnitudes. If they are the same, or if they differ only by sign [one is the negative version of the other] then the two lines are parallel.
This is the negative version of the magnitudes' product! This means that the two vectors are parallel.
Example Question #12 : Parallel And Perpendicular Vectors In Two Dimensions
Find the dot product of the two vectors
and
.
To find the dot product of two vectors,
find the product of the x-components,
find the product of the y-components,
and then find the sum.
Example Question #13 : Parallel And Perpendicular Vectors In Two Dimensions
Find the dot product of the two vectors
and
.
To find the dot product of two vectors,
find the product of the x-components,
find the product of the y-components,
and then find the sum.
Example Question #14 : Parallel And Perpendicular Vectors In Two Dimensions
Find the dot product of the two vectors
and
.
To find the dot product of two vectors,
find the product of the x-components,
find the product of the y-components,
and then find the sum.
Example Question #16 : Determine If Two Vectors Are Parallel Or Perpendicular
Evaluate the dot product of the following two vectors:
To find the dot product of two vectors, we multiply the corresponding terms of each vector and then add the results together, as expressed by the following formula:
Example Question #15 : Matrices And Vectors
Let
Find the dot product of the two vectors
.
Let
The dot product is equal to
.
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