Parametric Equations and Direction Vectors

The video tutorial explains how to find parametric equations for a line passing through two points in space. It introduces the concept of a direction vector and demonstrates how to calculate it using the coordinates of two points. The tutorial then shows how to derive parametric equations using one of the points and the direction vector. It also discusses the properties of parametric equations, emphasizing their non-uniqueness and the possibility of using any point on the line or scalar multiples of the direction vector.

What is the role of a direction vector in parametric equations?

• It is used to calculate the midpoint of the line.

• It defines the color of the line.

• It provides the coefficients for the variable t.

• It determines the length of the line.

How can the direction vector be found using two points?

• By dividing the coordinates of the terminal point by the initial point.

• By subtracting the coordinates of the initial point from the terminal point.

• By multiplying the coordinates of the two points.

• By adding the coordinates of the two points.

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CCSS.HSN.VM.A.2

What is the x component of the direction vector if the points are (3, -6, 7) and (5, 1, -4)?

• 1

• 5

• 2

• 3

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CCSS.HSN.VM.A.2

What is the z component of the direction vector if the points are (3, -6, 7) and (5, 1, -4)?

• 7

• -7

• 11

• -11

Which point is used to write the parametric equations in the given example?

• Point B with coordinates (5, 1, -4)

• Point A with coordinates (3, -6, 7)

• The midpoint of points A and B

• A random point on the line

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CCSS.HSA.CED.A.3

What is the parametric equation for y(t) using point A (3, -6, 7) and the direction vector (2, 7, -11)?

• y(t) = -6 + 7t

• y(t) = 3 + 2t

• y(t) = 7 - 11t

• y(t) = 1 + 5t

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CCSS.HSA.CED.A.3

What is the significance of the constant in the parametric equation x(t) = 3 + 2t?

• It represents the slope of the line.

• It is the x-coordinate of the point used to write the equation.

• It is the y-coordinate of the point used to write the equation.

• It is the z-coordinate of the point used to write the equation.

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CCSS.HSA.CED.A.3

Why are parametric equations not unique?

• Because they change with the time of day.

• Because they depend on the color of the graph.

• Because they can be written in different languages.

• Because any point on the line can be used to write them.

What happens if a different point on the line is used to write the parametric equations?

• The line will change direction.

• The line will become a curve.

• The equations will become invalid.

• The equations will look different but represent the same line.

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CCSS.5.G.A.2

How can the direction vector be altered without changing the line it represents?

• By using a scalar multiple of the direction vector.

• By rotating it 90 degrees.

• By reversing its direction.

• By changing its color.

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CCSS.5.G.A.2