Planes and the Vector Product flashcards

22 practice cards drawn from the Planes and the Vector Product lessons. Tap a card to turn it over. Every answer is checked against the lesson it came from.

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(2, 4, 0) × (4, 3, 0)

(0, 0, -10)

from “The Vector Product”

Which vector is at right angles to both (2, 2, 0) and (2, 4, 0)?

(0, 0, 4)

from “The Vector Product”

a × b has length 16. What is the area of the triangle with sides a and b?

8

from “Parallelogram Area from the Vector Product”

a × b = (3, 4, 12). What is the area of the parallelogram a and b span?

13

from “Parallelogram Area from the Vector Product”

Can (1, 3, 1) and (3, 9, 3) be the two directions of a plane?

no

from “The Vector Equation of a Plane”

r = (3, 3, 2) + λ(2, 1, 2) + μ(1, 2, 3). Which point has λ = 2 and μ = 1?

(8, 7, 9)

from “The Vector Equation of a Plane”

Which vector is normal to 3x − 1y + 3z = 6?

(3, -1, 3)

from “The Cartesian Equation of a Plane”

Which vector is normal to 3x − 4y + 4z = 6?

(3, -4, 4)

from “The Cartesian Equation of a Plane”

Which one gives the angle θ between a line of direction d and a plane of normal n?

sin θ = |d · n| ÷ (|d| |n|)

from “The Angle Between a Line and a Plane”

For a line and a plane, d · n = 3, |d| = 2 and |n| = 5. What is sin θ?

3/10

from “The Angle Between a Line and a Plane”

Which pair of vectors gives the angle between two planes?

their two normals

from “The Angle Between Two Planes”

Two planes have normals (3, 1, 3) and (6, 3, 6). Are the planes parallel?

no

from “The Angle Between Two Planes”

Substituting a line into a plane gives 0t = 0. What does that say?

the line lies inside the plane

from “The Intersection of a Line and a Plane”

Substituting the line into the plane gives 5t + 3 = 23. What is t?

4

from “The Intersection of a Line and a Plane”

P is (6, 6, 4) and sits 3 from a plane with normal (2, 1, 2), which has length 3. Where is the foot of the perpendicular?

(4, 5, 2)

from “The Distance from a Point to a Plane”

Which direction gives the shortest route from a point to a plane?

along the normal

from “The Distance from a Point to a Plane”

Which point lies on (x − 5)/4 = (y − 2)/4 = (z − 3)/4?

(5, 2, 3)

from “The Cartesian Form of a Line”

Write r = (2, 3, 3) + t(5, 3, 3) in Cartesian form.

(x − 2)/5 = (y − 3)/3 = (z − 3)/3

from “The Cartesian Form of a Line”

Where do r₁ = (1, 2, 0) + t(1, 1, 1) and r₂ = (5, 2, 4) + s(1, −1, 1) meet?

(3, 4, 2)

from “Intersecting and Skew Lines”

t = 1 and s = 0 fit the first two equations, and the third reads 4 = 7. What are the lines?

skew

from “Intersecting and Skew Lines”

Setting z = 0 leaves x + y = 6 and x + 2y = 14. Which point is on the line?

(−2, 8, 0)

from “The Intersection of Two Planes”

Two planes that are not parallel share what?

a line

from “The Intersection of Two Planes”

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