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Example Questions
Example Question #2 : Understanding Vector Calculations
Given vector and
, solve for
.
Â
To solve for , we need to add theÂ
components in the vector and theÂ
components together:
Example Question #4 : Vector
Given vector and
, solve for
.
Â
To solve for , we need to subtract theÂ
components in the vector and theÂ
components together:
Â
Example Question #3 : Understanding Vector Calculations
Given vector and
, solve for
.
Â
To solve for , We need to first multiplyÂ
into vectorÂ
to findÂ
and multiplyÂ
into vectorÂ
to find
; then we need to subtract theÂ
components in the vector and theÂ
components together:
Â
Â
Example Question #4 : Understanding Vector Calculations
Find the unit vector of .
To solve for the unit vector, the following formula must be used:
unit vector:
Â
Example Question #1 : Vector
Is a unit vector?
yes, because magnitude is equal to
no, because magnitude is not equal to
not enough information given
yes, because magnitude is equal to
To verify where a vector is a unit vector, we must solve for its magnitude. If the magnitude is equal to 1 then the vector is a unit vector:
 is a unit vector because magnitude is equal to
.
Â
Â
Â
Example Question #3 : Understanding Vector Calculations
Given vector . Solve for the direction (angle) of the vector:
To solve for the direction of a vector, we use the following formula:
=
with the vector being
Example Question #11 : Parametric, Polar, And Vector
Solve for vector given direction ofÂ
and magnitude of
.
To solve for a vector with the magnitude and direction given, we use the following formula:
Example Question #11 : Vector
Given vector and
, solve for
.
Â
To solve for , We need to multiplyÂ
into vectorÂ
to find
; then we need to subtract theÂ
components in the vector and theÂ
components together:
Example Question #11 : Parametric, Polar, And Vector
Find the magnitude of .
 therefore the vector is
To solve for the magnitude:
Â
Example Question #22 : Calculus Ii — Integrals
LetÂ
 andÂ
 be the following vectors: Â
 andÂ
. IfÂ
 is the acute angle between the vectors, then which of the following is equal toÂ
?
The cosine of the acute angle between two vectors is given by the following formula:
, whereÂ
 represents the dot product of the two vectors, Â
 is the magnitude of vector a, andÂ
 is the magnitude of vector b.
First, we will need to compute the dot product of the two vectors. Let's say we have two general vectors in space (three dimensions),  andÂ
. Let the components ofÂ
 beÂ
 and the components ofÂ
 beÂ
. Then the dot productÂ
 is defined as follows:
 .
Going back to the original problem, we can use this definition to find the dot product of   andÂ
.
The next two things we will need to compute are  andÂ
.Â
Let the components of a general vector  beÂ
. ThenÂ
 is defined asÂ
.
Thus, if   andÂ
, then
andÂ
.
Now, we put all of this information together to find the cosine of the angle between the two vectors.
We just need to simplify this.Â
.
In order to get it completely simplified, we have to rationalize the denominator by multiplying the numerator and denominator by the sqare root of 21.
.
We just have one more step. We need to solve for the value of the angle. In order to do this, we can take the inverse cosine of both sides of the equation.
.
The answer is .
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