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Question 1 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 2 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
Question 3 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 4 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 5 Report
Answer Details
Question 6 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 7 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 8 Report
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 9 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 10 Report
Answer Details
Question 11 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 12 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 13 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 14 Report
Answer Details
Question 15 Report
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 16 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 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
Answer Details
Question 19 Report
Express \( \frac{4\pi}{2} \) radians in degrees.
Question 20 Report
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 21 Report
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 22 Report
Answer Details
Question 23 Report
Answer Details
Question 24 Report
Answer Details
Question 25 Report
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 26 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 27 Report
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 28 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 29 Report
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 30 Report
Answer Details
6C2=6![6−2]![2!]
6∗5∗4!4!∗2!
= 6∗52
= 15
Question 31 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 32 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
Question 33 Report
If \( g(x) = \sqrt{1-x^2} \), find the domain of \( g(x) \)
Answer Details
Question 34 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 35 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
Question 36 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 37 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 38 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 39 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 40 Report
Answer Details
Question 41 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 42 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 43 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 44 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 |
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