Lesson 4.2.8.1
4.2.8.1 Vectors and vector operations Quiz: AQA Computer Science, Unit 2
20 questions
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Lesson 4.2.8.1, Vectors and vector operations: 20 multiple choice questions for the AQA Computer Science (7517), Unit 2: Fundamentals of data structures, written with Revision Ninja.
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The 20 questions
-
Which notation denotes a 4-vector over the reals?
- R4
- 4R with the reals as a multiplier
- N4 only, because vectors hold integers
- R/4, the quotient of the reals by four
-
In the function view of the vector [2.0, 3.14159, -1.0, 2.718281828], what does 1 maps to 3.14159 mean?
- The entry 1 is replaced by 3.14159
- The entry at index 1 is 3.14159
- Index 3.14159 is the largest index
- The vector has length 3.14159
-
Which Python list correctly represents the 2-vector over the reals with entries 2.0 and 3.0?
- 2.0 & 3.0
- (2.0 3.0)
- {2.0: 3.0}
- [2.0, 3.0]
-
For a vector viewed as a function f: S to R, with S = {0, 1, 2, 3}, what is the co-domain?
- R, the set of reals
- The set of all 4-tuples
- {0, 1, 2, 3}
- N, the set of natural numbers
-
Geometrically, what does vector addition achieve?
- Scaling of the vector's length
- Rotation of the vector about the origin
- Reflection in an axis
- Translation of the vector
-
Geometrically, what does scalar-vector multiplication achieve?
- Projection onto an axis
- Translation
- Reflection in the origin
- Scaling
-
For vectors u = [u1, ..., un] and v = [v1, ..., vn], which expression is the dot product?
- u1v1 x u2v2 x ... x unvn
- u1v1 + u2v2 + ... + unvn
- u1 + v1 + ... + un + vn
- (u1+v1)(u2+v2)...(un+vn)
-
What is the dot product of [1, 2, 3] and [4, 5, 6]?
- 27
- 15
- 21
- 32
-
What is the dot product of [3, 0] and [0, 4]?
- 7
- 0
- -12
- 12
-
What is the angle between the vectors [1, 1] and [1, 0]?
- 90 degrees
- 30 degrees
- 45 degrees
- 60 degrees
-
With alpha = 0.25 and beta = 0.75, what is the convex combination alpha u + beta v for u = [0, 0] and v = [4, 8]?
- [3, 6]
- [2, 4]
- [4, 8]
- [1, 2]
-
Which pair (alpha, beta) gives a valid convex combination alpha u + beta v?
- (0.3, 0.7)
- (-0.2, 1.2)
- (0.5, 0.6)
- (1, 1)
-
How is the vector [2, 3] represented as a dictionary in the spec's index-to-value form?
- {2: 0, 3: 1}
- {'x': 2, 'y': 3}
- [0: 2, 1: 3]
- {0: 2, 1: 3}
-
A 2-vector [2.0, 3.0] is drawn as an arrow with its tail at the origin. Where is the head?
- (0.0, 0.0)
- (2.0, 3.0)
- (5.0, 5.0)
- (3.0, 2.0)
-
If the dot product of two non-zero vectors is negative, what is the angle between them?
- Acute, less than 90 degrees
- Obtuse, greater than 90 degrees
- Exactly 90 degrees
- Zero degrees
-
What is the angle between u = [3, 4] and v = [4, 3], to one decimal place?
- About 53.1 degrees
- About 16.3 degrees
- About 74.0 degrees
- About 37.0 degrees
-
Let u = [0, 0] and v = [10, 0]. Which point is alpha u + beta v with alpha = 0.2 and beta = 0.8?
- [10, 0]
- [0.2, 0]
- [8, 0]
- [2, 0]
-
Compute a + b and then multiply the result by 2, where a = [1, 2] and b = [3, -1].
- [8, -2]
- [4, 2]
- [10, 4]
- [8, 2]
-
A vector is stored as the dictionary {0: 1.5, 1: -2.0, 2: 0.5}. Under the spec, is this a valid representation?
- No, dictionaries cannot represent vectors
- Yes, but only if the keys are strings
- No, keys must start at 1
- Yes, provided all values are drawn from the same field
-
Which pair of vectors is orthogonal?
- [1, 1] and [1, 1]
- [1, 2] and [2, 1]
- [3, 0] and [1, 1]
- [1, -2] and [2, 1]
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