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Question 1 Report
A particle is acted upon by forces F = (10N, 060º), P = (15N, 120º) and Q = (12N, 200º). Express the force that will keep the particle in equilibrium in the form xi + yj, where x and y are scalars.
Answer Details
Converting the forces to their rectangular forms
F = (10N, 060º)
Fx = 10cos60 = 5i
fy = 10sin60 = 8.66j
F = 5i + 8.66j
P = (15N, 120º)
Px = 15cos120 = -7.5i
py = 15sin120 = 12.99j
P = -7.5i + 12.99j
Q = (12N, 200º)
Qx = 12cos200 = -11.28i
Qy = 12sin200 = -4.1j
Q = -11.28i -4.1j
The resultant force = F + P + Q
R = 5i + 8.66j + (-7.5i + 12.99j) + (-11.28i -4.1j)
R = -13.78i + 17.55j
Question 2 Report
The length of the line joining points (x,4) and (-x,3) is 7 units. Find the value of x.
Answer Details
The problem provides us with two points, (x, 4) and (-x, 3), and tells us that the distance between them is 7 units. We need to find the value of x that satisfies this condition. To find the distance between two points, we can use the distance formula: d = sqrt((x2 - x1)^2 + (y2 - y1)^2) where (x1, y1) and (x2, y2) are the coordinates of the two points, and d is the distance between them. Using this formula, we can calculate the distance between the given points: d = sqrt((-x - x)^2 + (3 - 4)^2) d = sqrt(4x^2 + 1) We are given that this distance is equal to 7 units: sqrt(4x^2 + 1) = 7 To solve for x, we need to isolate it on one side of the equation. To do this, we will square both sides of the equation: 4x^2 + 1 = 49 Now we can solve for x: 4x^2 = 48 x^2 = 12 x = sqrt(12) = 2sqrt(3) Therefore, the value of x that satisfies the given conditions is 2sqrt(3), which is option D.
Question 3 Report
If \(f(x-1)=x^3+3x^2+4x-5\), find \(f(2)\)
Answer Details
x - 1 = 2
x = 3
f(2) = (3)3
+ 3(3)2
+ 4(3) - 5
f(2) = 27 + 27 + 12 - 5
= 61
Question 4 Report
The table shows the distribution of the distance (in km) covered by 40 hunters while hunting.
| Distance(km) | 3 | 4 | 5 | 6 | 7 | 8 |
| Frequency | 5 | 4 | x | 9 | 2x | 1 |
If a hunter is selected at random, find the probability that the hunter covered at least 6km.
Answer Details
5+4+x+9+2x+1 = 40
19+3x = 40
3x = 21
x = 7
| Distance(km) | 3 | 4 | 5 | 6 | 7 | 8 |
| Frequency | 5 | 4 | 7 | 9 | 14 | 1 |
The probability that the hunter covered at least 6km, means the hunter covered either 6km or 7km, or 8km.
24 hunters covered at least 6km
| 2440 | = | 35 |
Question 5 Report
The first, second and third terms of an exponential sequence (G.P) are (x - 4), (x + 2), and (3x + 1) respectively. Find the values of x.
Answer Details
U1 = x - 4
U2 = x + 2
U3 = 3x + 1
u2u1=u3u2
x+2x−4=3x+1x+2
(x+2)(x+2) = (x-4)(3x+1)
x2
+ 4x + 4 = 3x2 - 11x - 4
collecting like terms
2x2
- 15x - 8 =0
2x2
+ x - 16x - 8 = 0
x(2x + 1) - 8(2x + 1) = 0
(x-8)(2x+1) = 0
x = (−12,8 )
Question 6 Report
Given that P = {x: x is a multiple of 5}, Q = {x: x is a multiple of 3} and R = {x: x is an odd number} are subsets of μ = {x: 20 ≤ x ≤ 35}, (P⋃Q)∩R.
Answer Details
P = { 20, 25, 30, 35}, Q = {21, 24, 27, 30, 33}, R = {21, 23, 25, 27, 29, 31, 33, 35}
(P⋃Q)∩R = {20, 21, 24, 25, 27, 30, 33, 35} ∩ {21, 23, 25, 27, 29, 31, 33, 35}
= {21, 25, 27, 33, 35}
Question 7 Report
Express \( \frac{4\pi}{2} \) radians in degrees.
Question 8 Report
The equation of a circle is given as \(2x^2 + 2y^2 - x - 3y - 41 = 0\). Find the coordinates of its centre.
Answer Details
2x2 + 2y2 - x - 3y - 41
standard equation of circle
(x-a)2
+ (x-b)2
= r2
General form of equation of a circle.
x2
+ y2
+ 2gx + 2fy + c = 0
a = -g, b = -f., r2 = g2 + f2 - c
the centre of the circle is (a,b)
comparing the equation with the general form of equation of circle.
2x2
+ 2y2
- x - 3y - 41
= x2
+ y2
+ 2gx + 2fy + c
2x2
+ 2y2
- x - 3y - 41 = 0
divide through by 2
g = −14 ; 2g = −12
f = −34 ; 2f = −32
a = -g → - −14 ; = 14
b = -f → - (\frac{-3}{4}\) = (\frac{3}{4}\)
therefore the centre is (14 , 34 )
Question 9 Report
Evaluate \(4p_2 + 4C_2 - 4p_3\)
Answer Details
4p2+4C2−4p3
npr=n![n−r]!andnCr=n![n−r]!r!
= 4![4−2]!+4![4−2]!2!−4![4−3]!=4!2!+4!2!2!−4!1!
= 4∗3∗2!2!+4∗3∗2!2!2!−4∗3∗2∗11!
12 + 6 - 24 = -6
Question 10 Report
Evaluate \(\int_{0}^{1} x^{2}(x^{3}+2)^{3}\)
Answer Details
1∫0x2(x3+2)3 dx
let u=x3+2,du=3x2dx
when x = 1, u = 3
when x = 0, u = 2
dx = du3x2
3∫2 x2[u]33x2
3∫2 u33 du
= u43∗4 2 3
112[u4] 3
112[34−24]
112[81−16]
6512
Question 11 Report
If \( g(x) = \sqrt{1-x^2} \), find the domain of \( g(x) \)
Answer Details
1 - x2
≥ 0
-x2
≥ -1
x2
≤ 1
√x2
≤ 1
|x| ≤ 1
-1 ≤ x ≤ 1
Question 12 Report
Differentiate \( \frac{5x^3+x^2}{x} \), x ≠ 0 with respect to x.
Answer Details
5x3+x2x → 5x3x+x2x
5x2 + x
Then dy/dx = 10x + 1
Question 13 Report
If \(U_n = kn^2 + pn\), \(U_1 = -1\), \(U_5 = 15\), find the values of k and p.
Answer Details
Un = kn2 + pn,
U1 = -1,
U5 = 15,
when n = 1
U1 = k(1)2
+ p(1) = -1
k + p = -1 --------eqn1
when n = 5
U5
= k(5)2
+ p(5) = 15
25k + 5p = 15 --------eqn2
multiply eqn1 by 5 and eqn2 by 1
5k + 5p = -5 -------eqn3
25k + 5p = 15 -------eqn4
eqn4 - eqn3
20k = 20
k = 1
sub for k in eqn1
1 + p = -1
p = -1 -1 = -2
Question 14 Report
A linear transformation T is defined by T: (x,y) → (3x - y, x + 4y). Find the image of (2, -1) under T.
Answer Details
The linear transformation T is defined as T: (x, y) → (3x - y, x + 4y). To find the image of (2, -1) under T, we need to apply T to (2, -1) and see what we get. So, T(2, -1) = (3(2) - (-1), 2 + 4(-1)) = (7, -2) Therefore, the image of (2, -1) under T is (7, -2). Answer is correct.
Question 15 Report
The table shows the distribution of the distance (in km) covered by 40 hunters while hunting.
What is the mode of the distribution?
| Distance(km) | 3 | 4 | 5 | 6 | 7 | 8 |
| Frequency | 5 | 4 | x | 9 | 2x | 1 |
Answer Details
To find the mode of the distribution, we need to identify the value with the highest frequency. In the table, the frequency is given for each distance (in km) covered by the hunters. Let's first find the frequency of distance 5 km covered by the hunters. From the table, we know that the sum of all frequencies should be equal to 40, the total number of hunters. Sum of frequencies = 5 + 4 + x + 9 + 2x + 1 = 40 Simplifying the equation, we get: 3x + 19 = 40 3x = 21 x = 7 Now we know that the frequency of distance 5 km is x = 7. The frequencies for the other distances are: - Frequency of distance 3 km = 5 - Frequency of distance 4 km = 4 - Frequency of distance 6 km = 9 - Frequency of distance 7 km = 2x = 14 - Frequency of distance 8 km = 1 The highest frequency is 14, which corresponds to the distance of 7 km. Therefore, the mode of the distribution is 7 km. Hence, the answer is option (C) 7.
Question 16 Report
\[ \left(\frac{3\sqrt{6}}{\sqrt{5}}+\frac{\sqrt{54}}{3\sqrt{5}}\right)^{-1} \]
Answer Details
(3√6√5+√543√5 )−1
= √5(3√5)3√6+3√6
= 3∗56√6=52√6
= 5∗2√62√6+2√6=10√64∗6
= 5√612
Question 17 Report
If \( \log_{10}(3x+1) + \log_{10}4 = \log_{10}(9x+2) \), find the value of x
Answer Details
log10(3x+1)+log104=log10(9x+2)
log104(3x+1)=log10(9x+2)
4(3x+1) = 9x + 2
12x -4 = 9x + 2
12x - 9x = 2 + 4
3x = 6
x = 2
Question 18 Report
Find the coefficient of \(x^3y^2\) in the binomial expansion of \((x-2y)^5\)
Answer Details
x3 y2 in (x-2y)5
n = 5, r = 3, p = x, q = -2y
5C3 * x3 2
5C3 = 5![5−3]!3!
5∗4∗3!2!3! → 5∗42
5C3 = 10
: 5C3 * x3 -2y2 = 10 * x3 4y2
40x3
y2
the coefficient is 40
Question 19 Report
The mean heights of three groups of students consisting of 20, 16 and 14 students each are 1.67m, 1.50m and 1.40m respectively. Find the mean height of all the students.
Answer Details
To find the mean height of all the students, you need to add up the heights of all the students and divide by the total number of students. First, you need to find the total number of students, which is the sum of 20, 16 and 14 students, which is 50 students in total. Then, you need to find the total height of all the students by multiplying the number of students in each group by their respective mean height and adding them all up. Total height of all students = (20 x 1.67) + (16 x 1.50) + (14 x 1.40) = 33.4 + 24 + 19.6 = 77 meters Finally, to find the mean height of all the students, you need to divide the total height of all the students by the total number of students: Mean height of all students = Total height of all students / Total number of students = 77 / 50 = 1.54 meters Therefore, the answer is 1.54m.
Question 20 Report
A straight line makes intercepts of -3 and 2 on the x and y axes respectively. Find the equation of the line.
Answer Details
Recall:
| xa | + | yb | =1 |
Where 'a' and 'b' are the x and y intercept respectively.
| x-3 | + | y2 | =1 |
2x-3y = -6
2x - 3y + 6 = 0 -------(1)
multiply through by -1
-2x + 3y - 6 = 0
Question 21 Report
Given \(\begin{vmatrix} 2 & -3 \\ 1 & 4 \end{vmatrix}\begin{vmatrix} -6 \\ k \end{vmatrix}\begin{vmatrix} 3 \\ -26 \end{vmatrix} = 15\) Solve for k.
Answer Details
∣∣∣21−34∣∣∣∣∣∣−6k∣∣∣∣∣∣3−26∣∣∣=15
∣∣∣2[−6]1[−6]−3k+4k∣∣∣=∣∣∣3−26∣∣∣
∣∣∣−12−6−3k+4k∣∣∣=∣∣∣3−26∣∣∣
-12 - 3k = 3
-3k = 3 + 12
k = 15−3
k = -5
Question 22 Report
If 36, \( \frac{9}{4} \) and q are consecutive terms of an exponential sequence (G.P), find the sum of p and q.
Answer Details
GP : 36, P, q4 , q, ... p + q = ?
| Recall, | common | ratio, | r | = | TnTn-1 | = | T2T1 | = | T3T2 | = | T4T3 |
| ∴ | P36 | = | 94 | ÷ | p | ; | p2 | = | 94 | x | 36 | ; | p2 | = | 81 |
| p | = | 9 | ∴ | r | = | T2T1 | = | 936 | = | 14 |
| Also | r | = | T4T3 | = | q | ÷ | 94 |
∴ 14
= q ÷ 94
;
94 = 4q
| 16q | = | 9 | , | q | = | 916 | ∴ | p | + | q | = | 9 | + | 916 | = | 9 | 916 |
Question 23 Report
Find correct to the nearest degree, the acute angle formed by the lines y = 2x + 5 and 2y = x - 6
Answer Details
| tanθ | = | m1 - m21 + m1m2 |
y = 2x + 5
m1 = 2
2y = x - 6
| y | = | 12 | x | - | 3 |
| m2 | = | 12 |
| tanθ | = | 2 - 12 1+2(12 ) |
tanθ = 32 ÷ (1+1)
tanθ = 32 ÷ 2
| tanθ | = | 34 |
θ = tan−1(34)
θ = 36.87º
θ = 37º
Question 24 Report
The probability that a student will graduate from college is 0.4. If 3 students are selected from the college, what is the probability that at least one student will graduate?
Answer Details
To find the probability that at least one student will graduate, we can calculate the probability that no student will graduate and then subtract that from 1. The probability that a student will not graduate from college is 1 - 0.4 = 0.6. So, the probability that none of the three selected students will graduate is: 0.6 * 0.6 * 0.6 = 0.216 Therefore, the probability that at least one student will graduate is: 1 - 0.216 = 0.784 So, the answer is 0.78. In summary, the probability that at least one student will graduate from college given that 3 students are selected is 0.784 or 0.78, which is obtained by subtracting the probability that none of the three students will graduate from 1.
Question 25 Report
If \(x^2+y^2-2x-6y+5=0\), evaluate dy/dx when x=3 and y=2.
Answer Details
x2+y2+−2x−6y+5=0
When differentiated:
x2+y2+−2x−6y+5=0
where x=3 and y=2
2[3] + 2[2] - 8 = 0
6 + 4 - 8 = 2
Question 26 Report
Answer Details
This is a question about vector addition. To find →PR, we need to add →PQ and →RQ, but in reverse order (→PR = →PQ + →RQ). Given →PQ = -2i + 5j and →RQ = -i - 7j, we can add them as follows: →PR = →PQ + →RQ →PR = (-2i + 5j) + (-i - 7j) →PR = -2i - i + 5j - 7j →PR = -3i - 2j Therefore, the answer is "-3i - 2j". Option (B) "-3i + 12j", (C) "-i + 12j", and (D) "i - 12j" are incorrect.
Question 27 Report
Find the coefficient of \(x^2\) in the binomial expansion of \(\left(x+\frac{2}{x^2}\right)^5\)
Answer Details
(x+2x2)5
n = 5, r = 4, p = x and q = 2x2
5C4 x4 (2x2 )1 = 5C4 2x4x2
5C4 2x2 = 5![5−4]!4! * 2x2
5∗4!4!∗2x2 = 5 * 2x2 = 10x2
The coefficient is 10.
Question 28 Report
Find the range of values of x for which \(2x^2 + 7x - 15 \geq 0\).
Answer Details
2x2 + 7x - 15 ≥ 0
2x2
-3x + 10x - 15 ≥ 0
x(2x - 3) + 5(2x - 3) ≥ 0
(x+5)(2x-3) ≥ 0
the points on x-axis where the graph ≥ 0
x ≤ -5 or x ≥ 32
Question 29 Report
Given that P = (-4, -5) and Q = (2,3), express →PQ in the form (k,θ). where k is the magnitude and θ the bearing.
Answer Details
To find →PQ, we need to subtract the coordinates of point P from those of point Q, giving us: →PQ = Q - P = (2-(-4), 3-(-5)) = (6, 8) The magnitude, or length, of →PQ is found using the distance formula: k = √(6² + 8²) = √100 = 10 To find the bearing θ, we use trigonometry. The tangent of θ is the ratio of the opposite side (the change in y-coordinates) to the adjacent side (the change in x-coordinates): tan θ = 8/6 = 4/3 Using a calculator, we can find that θ is approximately 53.13º. However, we need to adjust this value depending on which quadrant →PQ lies in. Since both x and y are positive, →PQ lies in the first quadrant, so we don't need to make any adjustments. Therefore: θ = 53.13º So the vector →PQ can be expressed in the form (k,θ) as: (10 units, 53.13º) Therefore, the correct answer is (a) (10 units, 053º).
Question 30 Report
A binary operation ∆ is defined on the set of real numbers R, by \(x∆y = \sqrt{x+y-\frac{xy}{4}}\), where x, yER. Find the value of \(4∆3\)
Answer Details
x∆y = x+y−xy4−−−−−−−−−√
4∆3 = 4+3−4∗34−−−−−−−−−√
= 4+3−3−−−−−−−−√
= 4–√
= 2.
Question 31 Report
Simplify \( \frac{9 \ast 3^{n+1}-3^{n+2}}{3^{n+1}-3^n} \)
Answer Details
9∗3n+1−3n+23n+1−3n
= 3n∗3n∗31∗−32∗323n∗31−3n
= 3n(32∗31)3n(31−1)
= 27−93−1
= 182
= 9
Question 32 Report
A body of mass 18kg moving with velocity 4ms-1 collides with another body of mass 6kg moving in the opposite direction with velocity 10ms-1. If they stick together after the collision, find their common velocity.
Answer Details
m1u1 + m2u2 = (m1 + m2)v
m1 = 18kg, m2 = 6kg, u1 = 4ms-1, u2 = -10m/s
18(4) + 6(-10) = (18+6)v
72 - 60 = 24v
12 = 24v
v = 12
m/s
Question 33 Report
The functions \(f:x \to 2x^2 + 3x -7\) and \(g:x \to 5x^2 + 7x - 6\) are defined on the set of real numbers, R. Find the values of \(x\) for which \(3f(x) = g(x)\).
Answer Details
To find the values of x for which 3f(x) = g(x), we need to substitute the given functions f(x) and g(x) and then solve for x. Substituting the function f(x) = 2x^2 + 3x - 7, we get: 3f(x) = 3(2x^2 + 3x - 7) = 6x^2 + 9x - 21 Substituting the function g(x) = 5x^2 + 7x - 6, we get: g(x) = 5x^2 + 7x - 6 Now we can set these two equations equal to each other and solve for x: 6x^2 + 9x - 21 = 5x^2 + 7x - 6 Subtracting 5x^2 and 7x from both sides, we get: x^2 + 2x - 15 = 0 Factoring this quadratic equation, we get: (x + 5)(x - 3) = 0 Therefore, the values of x that satisfy the equation 3f(x) = g(x) are x = -5 and x = 3. Hence, the answer is: x = -5 or 3.
Question 34 Report
Evaluate \( \int_{-1}^{0} (x + 1)(x - 2)\,dx \)
Answer Details
∫0−1 (x + 1)(x - 2) dx
= ∫0−1 x2−x−2 dx
Integrated x2−x−2 = x33−x22−2
| = | (0 | - | 0 | - | 0) | - | ( | -13 | - | 12 | + | 2) |
| = | 0 | - | ( | 76 | ) | = | -76 |
Question 35 Report
Which of the following is the semi-interquartile range of a distribution?
Answer Details
The semi-interquartile range is a measure of variability in a dataset. To calculate it, we first need to find the median of the dataset, which is the middle value when the data is arranged in order from lowest to highest. Then, we need to find the quartiles, which are the values that divide the dataset into four equal parts. The semi-interquartile range is half of the difference between the upper quartile and the lower quartile. The upper quartile is the value that separates the highest 25% of the data from the lowest 75%, while the lower quartile is the value that separates the lowest 25% of the data from the highest 75%. Looking at the given options, the formula that corresponds to the semi-interquartile range is: 1/2 (Upper Quartile - Lower Quartile) Therefore, the correct answer is option d) "1/2 (Upper Quartile - Lower Quartile)".
Question 36 Report
A particle moving with a velocity of 5m/s accelerates at \(2\text{m/s}^2\). Find the distance it covers in 4 seconds.
Answer Details
from the equation of motion
u = 5m/s, a = 2m/s2
, t = 4s
s = ut + 12at2
s = 5*4 + 122∗42
s = 20 + 16
s = 36m
Question 37 Report
Solve: \(4\sin^2\theta + 1 = 2\), where \(0º < \theta < 180º\)
Answer Details
4sin2
2
θ + 1 = 2
4sin2 θ = 2 - 1
4sin2 θ = 1
s√in2θ
= 14−−√
sinθ = 12
θ = sin−112
θ = 30º 0r 150º
Question 38 Report
In how many ways can six persons be paired?
Answer Details
6C2=6![6−2]![2!]
6∗5∗4!4!∗2!
= 6∗52
= 15
Question 39 Report
A particle of mass 3kg moving along a straight line under the action of a F N, covers a line distance, d, at time, t, such that \(d = t^2 + 3t\). Find the magnitude of F at time t.
Answer Details
F = m * a
d = t2 + 3t.
a = d2ddt2
d[d]dt = 2t + 3
d2ddt2 = 2m/s2
a = 2m/s2
F = m * a
F = 3 × 2 = 6N
Question 40 Report
Given that \( \frac{8x+m}{x^2-3x-4} \equiv \frac{5}{x+1}+\frac{3}{x-4} \)
Answer Details
8x+mx2−3x−4≡5x+1+3x−4
8x+mx2−3x−4 ≡ 5(x−1)+3(x+4)x2−3x−4
multiplying both sides by x2-3x-4
8x+m ≡ 5(x-4)+3(x+1)
8x + m ≡ 5x - 20 + 3x + 3
8x - 5x - 3x + m = -20 + 3
m = -17
Question 41 Report
Consider the following statement:
x: All wrestlers are strong
y: Some wresters are not weightlifters.
Which of the following is a valid conclusion?
Answer Details
Question 42 Report
Solve: \(3^{2x-2}-28(3^{x-2})+3=0\)
Answer Details
32x−2−28(3x−2)+3=0
32x32−28.3x32+3=0
32x9−28.3x9+3=0
let p = 3x
p29−28p9+3=0
multiply through by 9
p2
- 28p + 27 = 0
p2
- p - 27p + 27 = 0
p (p - 1) - 27(p - 1) = 0
(p-1)(p-27) = 0
p = 1 or 27
when p = 1
p = 3x
3x
= 1
3x
= 30
x = 0
when p = 27
3x = 27
3x = 33
x = 3
Question 43 Report
The gradient of a function at any point (x,y) 2x - 6. If the function passes through (1,2), find the function.
Answer Details
dy/dx = 2x - 6
y = ∫ 2x - 6
y = 2x
2−6+c
y = x2
- 6x + c
passes through (1,2)
2 = 12
- 6(1) + c
2 = 1 - 6 + c
c = 7
y = x2
- 6x + c
y = x2 - 6x + 7
Question 44 Report
If α and β are roots of \(x^2 + mx - n = 0\), where m and n are constants, form the
| equation | whose | roots | are | 1α | and | 1β | . |
Answer Details
x2 + mx - n = 0
a = 1, b = m, c = -n
α + β = −ba = −m1 = -m
αβ = ca = −n1 = -n
the roots are = 1α and 1β
sum of the roots = 1α + 1β
1α + 1β α+βαβ
α + β = -m
αβ = -n
α+βαβ
product of the roots = 1α * 1β
1α
+ 1β
= 1αβ
→
x2
- (sum of roots)x + (product of roots)
x2
- ( m/n )x + ( 1/-n ) = 0
multiply through by n
nx2
- mx - 1 = 0
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