Mathematics
Q. Given vectors A = i + 2j + 3k and B = 4i + 5j + 6k, find A · B. (2019)
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Solution
A · B = (1)(4) + (2)(5) + (3)(6) = 4 + 10 + 18 = 32
Correct Answer: B — 34
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Q. How many ways can 2 boys and 3 girls be selected from 6 boys and 4 girls? (2023)
A.
60
B.
80
C.
100
D.
120
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Solution
The number of ways is 6C2 * 4C3 = 15 * 4 = 60.
Correct Answer: A — 60
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Q. How many ways can 4 students be selected from a class of 10? (2020)
A.
210
B.
120
C.
240
D.
300
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Solution
The number of ways to choose 4 students from 10 is given by 10C4 = 210.
Correct Answer: A — 210
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Q. If a + b = 12 and a^2 + b^2 = 70, what is the value of ab? (2019)
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Solution
Using the identity a^2 + b^2 = (a + b)^2 - 2ab, we have 70 = 12^2 - 2ab. Thus, 70 = 144 - 2ab, leading to ab = 37.
Correct Answer: A — 20
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Q. If a = 2 and b = 3, what is the value of (a + b)²?
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Solution
(a + b)² = (2 + 3)² = 5² = 25.
Correct Answer: A — 25
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Q. If a = 2 and b = 3, what is the value of a^2 + b^2?
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Solution
a^2 = 4 and b^2 = 9, so 4 + 9 = 13.
Correct Answer: C — 13
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Q. If A = 2i + 3j and B = 4i + 0j, what is the value of A · B? (2022)
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Solution
A · B = (2)(4) + (3)(0) = 8 + 0 = 8
Correct Answer: B — 8
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Q. If a = 4 and b = 5, what is the value of a² + b²?
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Solution
a² + b² = 4² + 5² = 16 + 25 = 41.
Correct Answer: A — 41
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Q. If A = 4i + 3j and B = 0i + 5j, what is A · B? (2019)
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Solution
A · B = (4)(0) + (3)(5) = 0 + 15 = 15
Correct Answer: B — 15
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Q. If A = 5i - 2j and B = -3i + 4j, calculate A · B. (2023)
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Solution
A · B = (5)(-3) + (-2)(4) = -15 - 8 = -23
Correct Answer: A — -23
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Q. If A = 7i + 1j and B = 2i + 3j, what is the scalar product A · B? (2022)
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Solution
A · B = (7)(2) + (1)(3) = 14 + 3 = 17
Correct Answer: A — 23
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Q. If a circle's radius is doubled, how does its area change? (2020)
A.
It remains the same
B.
It doubles
C.
It triples
D.
It quadruples
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Solution
Area = πr². If radius is doubled (2r), new area = π(2r)² = 4πr², which is quadruple the original area.
Correct Answer: D — It quadruples
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Q. If A is a 2x2 matrix and B is a 2x3 matrix, what is the order of the product AB? (2019)
A.
2x2
B.
2x3
C.
3x2
D.
2x5
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Solution
The order of the product of two matrices is determined by the outer dimensions. Here, A (2x2) and B (2x3) can be multiplied, resulting in a matrix of order 2x3.
Correct Answer: B — 2x3
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Q. If A is a 3x3 matrix, how many elements does it have? (2023)
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Solution
A 3x3 matrix has 3 rows and 3 columns, resulting in a total of 3 * 3 = 9 elements.
Correct Answer: B — 9
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Q. If a line has an equation of the form y = mx + c, what does 'c' represent? (2023)
A.
Slope
B.
Y-intercept
C.
X-intercept
D.
None of the above
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Solution
'c' represents the y-intercept of the line, which is the point where the line crosses the y-axis.
Correct Answer: B — Y-intercept
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Q. If a line has the equation 4x - y + 8 = 0, what is its y-intercept? (2019)
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Solution
Setting x = 0 in the equation gives y = 8. Thus, the y-intercept is -8.
Correct Answer: D — -4
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Q. If a line has the equation y = -3x + 6, what is the y-intercept?
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Solution
The y-intercept is the constant term in the equation, which is 6.
Correct Answer: A — 6
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Q. If a matrix is diagonal, what can be said about its non-diagonal elements? (2020)
A.
They are all zero
B.
They are all one
C.
They can be any value
D.
They are negative
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Solution
In a diagonal matrix, all non-diagonal elements are zero.
Correct Answer: A — They are all zero
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Q. If a parabola opens to the left, which of the following is its standard form?
A.
y^2 = -4px
B.
x^2 = -4py
C.
y^2 = 4px
D.
x^2 = 4py
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Solution
The standard form of a parabola that opens to the left is y^2 = -4px.
Correct Answer: A — y^2 = -4px
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Q. If a square has a perimeter of 32 cm, what is the length of one side? (2023)
A.
8 cm
B.
10 cm
C.
12 cm
D.
6 cm
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Solution
The perimeter P of a square is given by P = 4 * side. If P = 32 cm, then side = 32/4 = 8 cm.
Correct Answer: A — 8 cm
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Q. If a transversal intersects two parallel lines, what can be said about the same-side interior angles? (2023)
A.
They are equal
B.
They are supplementary
C.
They are complementary
D.
They are unequal
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Solution
When a transversal intersects two parallel lines, the same-side interior angles are supplementary, meaning they add up to 180 degrees.
Correct Answer: B — They are supplementary
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Q. If B = [[2, 3], [5, 7]], what is the value of det(B)? (2020)
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Solution
The determinant of B is calculated as (2*7) - (3*5) = 14 - 15 = -1.
Correct Answer: A — -1
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Q. If C = [[1, 0, 2], [0, 1, 3], [0, 0, 1]], what is det(C)? (2019)
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Solution
The determinant of an upper triangular matrix is the product of its diagonal elements. Here, det(C) = 1 * 1 * 1 = 1.
Correct Answer: B — 1
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Q. If cos B = 0.6, what is the value of sin B?
A.
0.8
B.
0.6
C.
0.4
D.
0.2
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Solution
Using the Pythagorean identity, sin B = √(1 - cos²B) = √(1 - 0.6²) = √(1 - 0.36) = √(0.64) = 0.8.
Correct Answer: A — 0.8
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Q. If cot A = 1, what is the value of A? (2022)
A.
45°
B.
90°
C.
60°
D.
30°
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Solution
Cotangent is 1 when the angle A is 45°, as cot A = cos A/sin A = 1 when both are equal.
Correct Answer: A — 45°
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Q. If cot D = 3/4, what is the value of sin D?
A.
3/5
B.
4/5
C.
5/3
D.
5/4
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Solution
cot D = 3/4 implies tan D = 4/3. Therefore, sin D = 4/5 (using the identity sin²D + cos²D = 1).
Correct Answer: A — 3/5
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Q. If D = [[4, 2], [1, 3]], find the inverse of D. (2022)
A.
[[3, -2], [-1, 4]]
B.
[[3, 2], [-1, 4]]
C.
[[3, -2], [1, 4]]
D.
[[4, -2], [-1, 3]]
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Solution
The inverse of D is given by (1/det(D)) * adj(D). Here, det(D) = (4*3) - (2*1) = 10, and adj(D) = [[3, -2], [-1, 4]]. Thus, D^(-1) = (1/10) * [[3, -2], [-1, 4]].
Correct Answer: A — [[3, -2], [-1, 4]]
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Q. If F = [[1, 2], [2, 4]], what is the determinant of F? (2021)
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Solution
The determinant of F is calculated as (1*4) - (2*2) = 4 - 4 = 0.
Correct Answer: A — 0
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Q. If f(x) = 3x + 2, what is the value of f(1) and is it continuous?
A.
5, Continuous
B.
5, Not Continuous
C.
3, Continuous
D.
3, Not Continuous
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Solution
f(1) = 3(1) + 2 = 5. Since f(x) is a linear function, it is continuous everywhere.
Correct Answer: A — 5, Continuous
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Q. If f(x) = e^x, what is f''(x)? (2020)
A.
e^x
B.
xe^x
C.
2e^x
D.
0
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Solution
The second derivative f''(x) = d^2/dx^2(e^x) = e^x.
Correct Answer: A — e^x
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