Calculus 3 : Calculus 3

Study concepts, example questions & explanations for Calculus 3

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Example Questions

Example Question #11 : Equations Of Lines And Planes

Find the unit tangent vector to the curve given by

Possible Answers:

Correct answer:

Explanation:

To find the unit tangent vector for a given curve, we must find the derivative of each of the components of the curve, and then divide this vector - the tangent vector - by the magnitude of the tangent vector itself.

To start, let's find the derivatives:

The derivatives were found using the following rules:

Next, we must find the magnitude of the tangent vector, by taking the square root of the sum of the squares the x, y, and z components. Note that the vector we were given was in unit vector notation, and i, j, and k are each equal to one unit, so they don't impact the magnitude of the vector (they simply indicate direction).

Finally, divide the vector by its magnitude:

Example Question #11 : Equations Of Lines And Planes

Find the unit tangent vector to the given curve:

Possible Answers:

Correct answer:

Explanation:

To find the unit tangent vector for a given curve, we must find the derivative of each of the components of the curve, and then divide this vector - the tangent vector - by the magnitude of the tangent vector itself.

To start, let's find the derivatives:

The derivatives were found using the following rules:

Next, we must find the magnitude of the tangent vector, by taking the square root of the sum of the squares the x, y, and z components. Note that the vector we were given was in unit vector notation, and i, j, and k are each equal to one unit, so they don't impact the magnitude of the vector (they simply indicate direction).

Finally, divide the tangent vector by its magnitude:

Example Question #13 : 3 Dimensional Space

Find the unit tangent vector given by the curve

Possible Answers:

Correct answer:

Explanation:

To find the unit tangent vector for a given curve, we must find the derivative of each of the components of the curve, and then divide this vector - the tangent vector - by the magnitude of the tangent vector itself.

To start, let's find the derivatives:

We used the following rules to find them:

Next, we must find the magnitude of the tangent vector, by taking the square root of the sum of the squares the x, y, and z components. Note that the vector we were given was in unit vector notation, and i, j, and k are each equal to one unit, so they don't impact the magnitude of the vector (they simply indicate direction).

Finally, divide the tangent vector by its magnitude:

Example Question #131 : Calculus 3

Write the equation of the line - in vector form - passing through the two points

 

Possible Answers:

Correct answer:

Explanation:

To find the equation of the line, we first must find the vector passing between the two points:

This was found by 

Next, we pick one point, and using the formula

we get our line:

Example Question #11 : Equations Of Lines And Planes

Write the equation for the plane containing the points

Possible Answers:

Correct answer:

Explanation:

To find the equation of the plane, we need a point on the plane, and the normal vector to the plane, which is given by the cross product of two vectors in the plane.

To start, let's find these vectors:

We found them by subtracting the terminal point (B, C) and the initial point (A, B, respectively).

Now, we can write the determinant in order to take the cross product of the two vectors:

where i, j, and k are the unit vectors corresponding to the x, y, and z direction respectively.

Next, we take the cross product. One can do this by multiplying across from the top left to the lower right, and continuing downward, and then subtracting the terms multiplied from top right to the bottom left:

The equation of a plane is given by

, where  is the normal vector and  is any point on the plane.

Using our normal vector  and the point , we get the equation

Example Question #131 : Calculus 3

Find the equation of the plane given by the three points

Possible Answers:

Correct answer:

Explanation:

To find the equation of the plane given by three points, we need the normal vector to the plane and a point on the plane.

We first must find two vectors on the plane:

These were found by taking the difference between the first and second, and second and third points respectively.

Now, we can write the determinant in order to take the cross product of the two vectors:

where i, j, and k are the unit vectors corresponding to the x, y, and z direction respectively.

Next, we take the cross product. One can do this by multiplying across from the top left to the lower right, and continuing downward, and then subtracting the terms multiplied from top right to the bottom left:

Now, we plug this, and a point of our choosing, into the equation for a plane:

, where  is the normal vector and  is any given point.

Plugging this in, we get

Example Question #131 : Calculus 3

Find the equation of the plane that contains the point , and has a normal vector 

Possible Answers:

Correct answer:

Explanation:

Using the formula for a plane , where the point given is  and the normal vector is . Plugging in the known values, you get . Manipulating this equation through algebra gives you the answer 

Example Question #132 : Calculus 3

Write the equation of the plane given by the three points

Possible Answers:

Correct answer:

Explanation:

To find the equation of a plane, we need a point on the plane and the normal vector to the plane. 

First, we must find two vectors on the plane using the given points (taking the difference between the two points in each vector):

Now, we can write the determinant in order to take the cross product of the two vectors:

where i, j, and k are the unit vectors corresponding to the x, y, and z direction respectively.

Next, we take the cross product. One can do this by multiplying across from the top left to the lower right, and continuing downward, and then subtracting the terms multiplied from top right to the bottom left:

Now, we choose a point (for example, ) and use the normal vector given by  from the cross product:

Plugging all of this in, and simplifying, we get

Example Question #133 : Calculus 3

Find the equation of the plane that contains the point  and has a normal vector .

Possible Answers:

Correct answer:

Explanation:

The formula of a plane containing a point  and with a normal vector  is 

,

Using what we were given, we get 

.

Through algebra, we get 

.

Example Question #134 : Calculus 3

Find the equation of the plane that contains the point  and has a normal vector .

Possible Answers:

Correct answer:

Explanation:

Using the formula for a plane, we have

,

where the point given is  and the normal vector is .

Plugging in the known values, you get 

.

Manipulating this equation through algebra gives you the answer 

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