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Pregunta 1 Informe
A fair coin is tossed 3 times. Find the probability of obtaining exactly 2 heads.
Detalles de la respuesta
When a fair coin is tossed once, there are two possible outcomes, either heads or tails. Therefore, the probability of obtaining heads is \(\frac{1}{2}\) and the probability of obtaining tails is also \(\frac{1}{2}\). Now, when a fair coin is tossed 3 times, there are \(2^3 = 8\) possible outcomes as each toss has 2 possible outcomes (heads or tails). These 8 possible outcomes are: HHH, HHT, HTH, THH, HTT, THT, TTH, TTT Out of these 8 outcomes, we need to find the probability of obtaining exactly 2 heads. We can count the number of outcomes in which exactly 2 heads are obtained as follows: - HHT - HTH - THH Therefore, there are 3 outcomes in which exactly 2 heads are obtained. So, the probability of obtaining exactly 2 heads is: \[\frac{\text{number of outcomes in which exactly 2 heads are obtained}}{\text{total number of possible outcomes}} = \frac{3}{8}\] Hence, the answer is \(\frac{3}{8}\).
Pregunta 2 Informe
Solve for x in the equation \(5^{x} \times 5^{x + 1} = 25\).
Detalles de la respuesta
To solve the equation \(5^{x} \times 5^{x + 1} = 25\), we can use the rules of exponents. Since the bases are the same (both are 5), we can add the exponents to get: $$5^{x} \times 5^{x + 1} = 5^{2}$$ $$5^{2x + 1} = 5^{2}$$ Now we can solve for x by equating the exponents: $$2x + 1 = 2$$ $$2x = 1$$ $$x = \frac{1}{2}$$ Therefore, the solution is \(\frac{1}{2}\).
Pregunta 3 Informe
Consider the statements:
p : Musa is short
q : Musa is brilliant
Which of the following represents the statement "Musa is short but not brilliant"?
Detalles de la respuesta
The statement "Musa is short but not brilliant" consists of two parts: "Musa is short" and "Musa is not brilliant". Using the statements p and q, we can represent "Musa is short" as p, and "Musa is not brilliant" as \(\sim q\), where \(\sim\) means "not". Now we need to find the logical operator that connects p and \(\sim q\) to form the statement "Musa is short but not brilliant". This operator is the logical AND, represented by \(\wedge\). Therefore, the statement "Musa is short but not brilliant" is represented by: \(p \wedge \sim q\).
Pregunta 4 Informe
Given that \(r = 3i + 4j\) and \(t = -5i + 12j\), find the acute angle between them.
Detalles de la respuesta
Pregunta 5 Informe
A ball falls from a height of 18m above the ground. Find the speed with which the ball hits the ground. \([g = 10ms^{-2}]\)
Detalles de la respuesta
We can use the formula for the final velocity of an object falling from a height under the influence of gravity: $v^2 = u^2 + 2gh$ where $v$ is the final velocity, $u$ is the initial velocity (in this case, 0), $g$ is the acceleration due to gravity and $h$ is the height from which the object is falling. Substituting the given values, we have: $v^2 = 0 + 2\times10\times18 = 360$ Taking the square root of both sides, we get: $v = \sqrt{360} = 6\sqrt{10} \approx 18.97ms^{-1}$ Therefore, the speed with which the ball hits the ground is approximately 18.97\(ms^{-1}\). Hence, the correct option is (d) 18.97\(ms^{-1}\).
Pregunta 6 Informe
A man of mass 80kg stands in a lift. If the lift moves upwards with acceleration 0.5\(ms^{-2}\), calculate the reaction from the floor of the lift on the man. \([g = 10ms^{-2}]\)
Detalles de la respuesta
Pregunta 7 Informe
Find the gradient to the normal of the curve \(y = x^{3} - x^{2}\) at the point where x = 2.
Detalles de la respuesta
To find the gradient to the normal, we need to find the gradient of the tangent and then take the negative reciprocal of that value. To find the gradient of the tangent, we need to differentiate the equation of the curve. \[\frac{dy}{dx} = 3x^{2} - 2x\] At the point where x = 2, the gradient of the tangent is: \[\frac{dy}{dx}\Bigr|_{x=2} = 3(2)^{2} - 2(2) = 8\] So the gradient to the normal is the negative reciprocal of 8: \[\frac{-1}{8}\] Therefore, the answer is (a) \(\frac{-1}{8}\).
Pregunta 8 Informe
If \(P = {x : -2 < x < 5}\) and \(Q = {x : -5 < x < 2}\) are subsets of \(\mu = {x : -5 \leq x \leq 5}\), where x is a real number, find \((P \cup Q)\).
Detalles de la respuesta
Pregunta 9 Informe
Given that \(n = 10\) and \(\sum d^{2} = 20\), calculate the Spearman's rank correlation coefficient.
Detalles de la respuesta
Spearman's rank correlation coefficient is a measure of the strength of a relationship between two variables and is used when the variables are measured on an ordinal scale. The formula for calculating Spearman's rank correlation coefficient is: $$r_{s} = 1 - \frac{6\sum d^{2}}{n(n^{2} - 1)}$$ where \(d\) is the difference between the ranks of each observation in the two variables, and \(n\) is the sample size. In this case, we are given that \(n = 10\) and \(\sum d^{2} = 20\). Substituting these values into the formula, we get: $$r_{s} = 1 - \frac{6(20)}{10(10^{2} - 1)} = 1 - \frac{120}{990} = 1 - 0.121 = 0.879$$ Therefore, the Spearman's rank correlation coefficient is 0.879.
Pregunta 10 Informe
If \(\log_{10}y + 3\log_{10}x \geq \log_{10}x\), express y in terms of x.
Detalles de la respuesta
We can start by using the logarithmic rule that states: \(\log_{a}b + \log_{a}c = \log_{a}(bc)\). So, we can rewrite the given inequality as follows: \[\log_{10}y + 3\log_{10}x \geq \log_{10}x\] \[\Rightarrow \log_{10}(yx^{3}) \geq \log_{10}x\] \[\Rightarrow yx^{3} \geq x\] Dividing both sides by \(x\) (since \(x > 0\)), we get: \[yx^{2} \geq 1\] \[\Rightarrow y \geq \frac{1}{x^{2}}\] Therefore, the answer is \(y \geq \frac{1}{x^{2}}\).
Pregunta 11 Informe
Points E(-2, -1) and F(3, 2) are the ends of the diameter of a circle. Find the equation of the circle.
Detalles de la respuesta
Pregunta 12 Informe
Find \(\lim\limits_{x \to 3} \frac{2x^{2} + x - 21}{x - 3}\).
Detalles de la respuesta
Pregunta 13 Informe
If \(\begin{vmatrix} m-2 & m+1 \\ m+4 & m-2 \end{vmatrix} = -27\), find the value of m.
Detalles de la respuesta
The determinant of a 2x2 matrix is given by the formula: \(\begin{vmatrix} a & b \\ c & d \end{vmatrix} = ad - bc\) Using this formula, we can find the determinant of the given matrix: \(\begin{vmatrix} m-2 & m+1 \\ m+4 & m-2 \end{vmatrix} = (m-2)(m-2) - (m+1)(m+4)\) Simplifying this expression, we get: \((m-2)^2 - (m+1)(m+4) = m^2 - 4m + 4 - (m^2 + 5m + 4) = -9m\) Setting this equal to the given determinant of -27, we have: \(-9m = -27\) Solving for m, we get: \(m = 3\) Therefore, the answer is: \(3\).
Pregunta 14 Informe
Given that \(-6, -2\frac{1}{2}, ..., 71\) is a linear sequence , calculate the number of terms in the sequence.
Detalles de la respuesta
Pregunta 15 Informe
The remainder when \(x^{3} - 2x + m\) is divided by \(x - 1\) is equal to the remainder when \(2x^{3} + x - m\) is divided by \(2x + 1\). Find the value of m.
Detalles de la respuesta
Pregunta 16 Informe
The radius of a circle increases at a rate of 0.5\(cms^{-1}\). Find the rate of change in the area of the circle with radius 7cm. \([\pi = \frac{22}{7}]\)
Detalles de la respuesta
We know that the area of a circle is given by the formula: $$A = \pi r^2$$ We need to find the rate of change of the area of the circle, i.e., \(\frac{dA}{dt}\). We can use differentiation to find the rate of change of the area with respect to time: $$\frac{dA}{dt} = \frac{d}{dt} (\pi r^2)$$ Since the radius is increasing at a rate of 0.5\(cms^{-1}\), we have: $$\frac{dr}{dt} = 0.5$$ Using the chain rule of differentiation, we have: $$\frac{dA}{dt} = \frac{dA}{dr} \cdot \frac{dr}{dt} = 2 \pi r \cdot 0.5 = \pi r$$ Substituting the given value of the radius, we get: $$\frac{dA}{dt} = \pi \cdot 7 = 22\(cm^{2}s^{-1}\)$$ Therefore, the rate of change in the area of the circle with radius 7cm is 22\(cm^{2}s^{-1}\). Hence, the correct option is: 22\(cm^{2}s^{-1}\).
Pregunta 17 Informe
The lines \(2y + 3x - 16 = 0\) and \(7y - 2x - 6 = 0\) intersect at point P. Find the coordinates of P.
Detalles de la respuesta
Pregunta 18 Informe
If \(P = \begin{pmatrix} 1 & 2 \\ 5 & 1 \end{pmatrix}\) and \(Q = \begin{pmatrix} 0 & 1 \\ 1 & 3 \end{pmatrix}\), find PQ.
Detalles de la respuesta
To find the product PQ of matrices P and Q, we multiply the elements of each row of matrix P by the corresponding elements of each column of matrix Q, and add up the products. Thus, we have: \begin{align*} PQ &= \begin{pmatrix} 1 & 2 \\ 5 & 1 \end{pmatrix} \begin{pmatrix} 0 & 1 \\ 1 & 3 \end{pmatrix} \\ &= \begin{pmatrix} (1)(0)+(2)(1) & (1)(1)+(2)(3) \\ (5)(0)+(1)(1) & (5)(1)+(1)(3) \end{pmatrix} \\ &= \begin{pmatrix} 2 & 7 \\ 1 & 8 \end{pmatrix} \end{align*} Therefore, the answer is option (C): \(\begin{pmatrix} 2 & 7 \\ 1 & 8 \end{pmatrix}\).
Pregunta 19 Informe
Find an expression for y given that \(\frac{\mathrm d y}{\mathrm d x} = x^{2}\sqrt{x}\)
Detalles de la respuesta
Pregunta 20 Informe
If \(f(x) = \frac{4}{x} - 1, x \neq 0\), find \(f^{-1}(7)\).
Detalles de la respuesta
To find \(f^{-1}(7)\), we need to find the value of \(x\) for which \(f(x) = 7\). So, we start by setting \(f(x) = 7\) and solving for \(x\): \begin{align*} f(x) &= 7 \\ \frac{4}{x} - 1 &= 7 \\ \frac{4}{x} &= 8 \\ x &= \frac{4}{8} \\ x &= \frac{1}{2} \end{align*} Therefore, \(f^{-1}(7) = \frac{1}{2}\). So, the correct option is: - \(\frac{1}{2}\)
Pregunta 21 Informe
If \(y = 4x - 1\), list the range of the domain \({-2 \leq x \leq 2}\), where x is an integer.
Detalles de la respuesta
The given equation is \(y = 4x - 1\), which represents a linear function where the output value of \(y\) depends on the input value of \(x\). The domain of the function is defined as the set of all possible input values of \(x\) that the function can take. Here, the domain of the function is given as \({-2 \leq x \leq 2}\), which means that \(x\) can take integer values between -2 and 2 (both inclusive). To find the range of the function, we need to substitute the given values of \(x\) in the equation and calculate the corresponding values of \(y\). When we substitute \(x = -2\), we get \(y = 4(-2) - 1 = -9\). When we substitute \(x = -1\), we get \(y = 4(-1) - 1 = -5\). When we substitute \(x = 0\), we get \(y = 4(0) - 1 = -1\). When we substitute \(x = 1\), we get \(y = 4(1) - 1 = 3\). When we substitute \(x = 2\), we get \(y = 4(2) - 1 = 7\). Therefore, the range of the function for the given domain is {-9, -5, -1, 3, 7}.
Pregunta 22 Informe
If the solution set of \(x^{2} + kx - 5 = 0\) is (-1, 5), find the value of k.
Detalles de la respuesta
To solve this problem, we can use the fact that the sum and product of the roots of a quadratic equation are related to its coefficients. Specifically, for the equation \(ax^2+bx+c=0\), the sum of the roots is given by \(-b/a\) and the product of the roots is given by \(c/a\). In this problem, we are given that the solution set of \(x^2+kx-5=0\) is (-1, 5). This means that the quadratic equation has roots -1 and 5. Therefore, we can write the equation in factored form as \((x+1)(x-5)=0\). Expanding this expression, we get: $$x^2-4x-5=0$$ Comparing this to the original equation \(x^2+kx-5=0\), we can see that \(k=-4\). Therefore, the answer is (B) -4. Alternatively, we can use the sum and product of roots formula to solve for k. Since the roots of the equation are -1 and 5, we know that: $$-b/a=-1+5=4$$ and $$c/a=-5$$ Using the fact that \(a=1\), we can solve for \(b\) and \(c\): $$b=-a(-b/a)=4(1)=4$$ $$c=a(c/a)=1(-5)=-5$$ Therefore, the original equation is \(x^2+4x-5=0\), and the answer is (B) -4.
Pregunta 23 Informe
An operation * is defined on the set, R, of real numbers by \(p * q = p + q + 2pq\). If the identity element is 0, find the value of p for which the operation has no inverse.
Detalles de la respuesta
To find the value of p for which the operation has no inverse, we need to solve for the value of p that makes the equation \(p * q = q * p = 0\) have no solution for q other than q = 0. Let's set up the equation: \[p * q = q * p = p + q + 2pq\] We want to find the value of p that makes the equation have no solution for q other than q = 0. So let's substitute q = 0: \[p * 0 = 0 * p = p + 0 + 2p(0)\] \[p = 0\] Now, let's check if there is any other value of p that would make the equation have no solution for q other than q = 0. If p is not 0, we can rewrite the equation as: \[q = \frac{-p}{2p + 1}\] Now, if p is any value other than \(-\frac{1}{2}\), the denominator 2p+1 will not be zero, which means that there will always be a real number q that satisfies the equation. However, if p = \(-\frac{1}{2}\), the denominator becomes zero, which means that the equation has no solution for q other than q = 0. Therefore, the value of p for which the operation has no inverse is \(-\frac{1}{2}\), and the answer is option A: \(\frac{-1}{2}\).
Pregunta 24 Informe
Given that \(\tan x = \frac{5}{12}\), and \(\tan y = \frac{3}{4}\), Find \(\tan (x + y)\).
Detalles de la respuesta
Pregunta 25 Informe
A force 10N acts in the direction 060° and another force 6N acts in the direction 330°. Find the y component of their resultant force.
Detalles de la respuesta
We can use vector addition to find the resultant force, then take the y component of it. First, we need to convert the forces into their x and y components. For the force of 10N at 060°, the x component is 10 cos(60°) = 5 N and the y component is 10 sin(60°) = 5√3 N. For the force of 6N at 330°, the x component is 6 cos(330°) = 3√3 N and the y component is 6 sin(330°) = -3 N. To find the resultant force, we add the x components and the y components separately: x component: 5 N + 3√3 N = 5 N + 5.2 N = 10.2 N y component: 5√3 N - 3 N = 8.66 N So the y component of the resultant force is 8.66 N. Therefore, the answer is (B) \((-3 + 5\sqrt{3})N\).
Pregunta 26 Informe
The 3rd and 6th terms of a geometric progression (G.P.) are \(\frac{8}{3}\) and \(\frac{64}{81}\) respectively, find the common ratio.
Detalles de la respuesta
Pregunta 27 Informe
Find the unit vector in the direction of \(-2i + 5j\).
Detalles de la respuesta
To find the unit vector in the direction of \(-2i + 5j\), we need to first find the magnitude of the vector and then divide the vector by its magnitude. The magnitude of the vector \(-2i + 5j\) is given by: \begin{align*} \sqrt{(-2)^2 + (5)^2} &= \sqrt{4+25} \\ &= \sqrt{29} \end{align*} Therefore, the unit vector in the direction of \(-2i + 5j\) is: \begin{align*} \frac{1}{\sqrt{29}}(-2i + 5j) &= \frac{1}{\sqrt{29}}\begin{pmatrix}-2 \\ 5\end{pmatrix} \\ &= \frac{1}{\sqrt{29}}\begin{pmatrix}-2/1 \\ 5/1\end{pmatrix} \\ &= \boxed{\frac{1}{\sqrt{29}}(-2i + 5j)} \end{align*} Therefore, option (B) is the correct answer.
Pregunta 28 Informe
Express \(\frac{8 - 3\sqrt{6}}{2\sqrt{3} + 3\sqrt{2}}\) in the form \(p\sqrt{3} + q\sqrt{2}\).
Detalles de la respuesta
Pregunta 30 Informe
Evaluate \(\cos 75°\), leaving the answer in surd form.
Detalles de la respuesta
We can use the trigonometric identity \(\cos 75^\circ = \cos(45^\circ+30^\circ) = \cos 45^\circ \cos 30^\circ - \sin 45^\circ \sin 30^\circ\). We know that \(\cos 45^\circ = \frac{\sqrt{2}}{2}\) and \(\sin 45^\circ = \frac{\sqrt{2}}{2}\), and we can find \(\cos 30^\circ\) and \(\sin 30^\circ\) using a 30-60-90 triangle or the unit circle. In either case, we get \(\cos 30^\circ = \frac{\sqrt{3}}{2}\) and \(\sin 30^\circ = \frac{1}{2}\). Substituting these values, we have: \begin{align*} \cos 75^\circ &= \cos(45^\circ+30^\circ) \\ &= \cos 45^\circ \cos 30^\circ - \sin 45^\circ \sin 30^\circ \\ &= \frac{\sqrt{2}}{2} \cdot \frac{\sqrt{3}}{2} - \frac{\sqrt{2}}{2} \cdot \frac{1}{2} \\ &= \frac{\sqrt{6}}{4} - \frac{\sqrt{2}}{4} \\ &= \frac{\sqrt{6} - \sqrt{2}}{4} \end{align*} Therefore, the answer is \(\frac{\sqrt{2}}{4}(\sqrt{3} - 1)\).
Pregunta 32 Informe
Find the fourth term in the expansion of \((3x - y)^{6}\).
Detalles de la respuesta
To find the fourth term in the expansion of \((3x - y)^6\), we can use the binomial theorem, which states that the \(r\)th term in the expansion of \((a+b)^n\) is given by: \[\binom{n}{r}a^{n-r}b^r\] In this case, \(a = 3x\) and \(b = -y\) (note the negative sign). So, using the binomial theorem, the fourth term in the expansion of \((3x - y)^6\) is: \[\binom{6}{3}(3x)^3(-y)^3 = \frac{6!}{3!3!}(27x^3)(-y^3) = -540x^3y^3\] Therefore, the answer is \(-540x^{3}y^{3}\).
Pregunta 33 Informe
Find the minimum value of \(y = 3x^{2} - x - 6\).
Detalles de la respuesta
To find the minimum value of the quadratic function, we first need to find the vertex of the parabola. We can do this by using the formula: \(-\frac{b}{2a}\) where \(a\) is the coefficient of the squared term, and \(b\) is the coefficient of the linear term. In this case, \(a = 3\) and \(b = -1\), so: \(-\frac{b}{2a} = -\frac{-1}{2(3)} = \frac{1}{6}\) This tells us that the vertex of the parabola occurs at \(x = \frac{1}{6}\). To find the minimum value of the function, we substitute this value of \(x\) into the function: \(y = 3\left(\frac{1}{6}\right)^{2} - \frac{1}{6} - 6 = -6\frac{1}{12} = -\frac{25}{4}\) Therefore, the minimum value of the function is \(-6\frac{1}{12}\), which is equivalent to \(-\frac{25}{4}\). So the answer is option B.
Pregunta 34 Informe
Factorize completely: \(x^{2} + x^{2}y + 3x - 10y + 3xy - 10\).
Detalles de la respuesta
Pregunta 35 Informe
A box contains 14 white balls and 6 black balls. Find the probability of first drawing a black ball and then a white ball without replacement.
Detalles de la respuesta
Pregunta 36 Informe
Find the coefficient of \(x^{3}\) in the expansion of \([\frac{1}{3}(2 + x)]^{6}\).
Detalles de la respuesta
The binomial theorem states that the term containing \(x^r\) in the expansion of \((a+b)^n\) is given by: $$\frac{n!}{r!(n-r)!}a^{n-r}b^{r}$$ In this case, we have \([\frac{1}{3}(2 + x)]^{6}\), so \(a = \frac{2}{3}\) and \(b = \frac{1}{3}x\). We want to find the coefficient of \(x^3\), so \(r = 3\). Using the formula above, the term containing \(x^3\) is: $$\frac{6!}{3!(6-3)!}\left(\frac{2}{3}\right)^3\left(\frac{1}{3}x\right)^3 = 20\times\frac{8}{27}\times\frac{1}{27}x^3 = \frac{160}{2187}x^3$$ Therefore, the coefficient of \(x^3\) in the expansion is \(\boxed{\frac{160}{729}}\).
Pregunta 37 Informe
Given n = 3, evaluate \(\frac{1}{(n-1)!} - \frac{1}{(n+1)!}\)
Detalles de la respuesta
We are given that n=3. Substituting n=3, we have: \(\frac{1}{(n-1)!} - \frac{1}{(n+1)!} = \frac{1}{(3-1)!} - \frac{1}{(3+1)!} = \frac{1}{2!} - \frac{1}{4!}\) Evaluating the factorials, we get: \(\frac{1}{2!} - \frac{1}{4!} = \frac{1}{2} - \frac{1}{24} = \frac{12}{24} - \frac{1}{24} = \frac{11}{24}\) Therefore, the value of \(\frac{1}{(n-1)!} - \frac{1}{(n+1)!}\) when n=3 is \(\frac{11}{24}\). Hence, the answer is, \(\frac{11}{24}\).
Pregunta 38 Informe
Find the equation of the line which passes through (-4, 3) and parallel to line y = 2x + 5.
Detalles de la respuesta
To find the equation of a line that is parallel to a given line, we need to use the fact that parallel lines have the same slope. The given line has a slope of 2 (since it is in the form y = mx + b, where m is the slope and b is the y-intercept). Therefore, any line parallel to it must also have a slope of 2. We also know that the line passes through the point (-4, 3). We can use the point-slope form of the equation of a line to find the equation of the line: y - y1 = m(x - x1) where (x1, y1) is the point the line passes through, and m is the slope. Substituting in the values we know, we get: y - 3 = 2(x - (-4)) Simplifying: y - 3 = 2(x + 4) y - 3 = 2x + 8 y = 2x + 11 Therefore, the equation of the line which passes through (-4, 3) and parallel to line y = 2x + 5 is y = 2x + 11. So the answer is: y = 2x + 11.
Pregunta 39 Informe
Find the variance of 11, 12, 13, 14 and 15.
Detalles de la respuesta
To find the variance, first we need to calculate the mean of the given data set: Mean = (11+12+13+14+15)/5 = 13 Next, we subtract the mean from each data point and square the differences: (11-13)^2 = 4 (12-13)^2 = 1 (13-13)^2 = 0 (14-13)^2 = 1 (15-13)^2 = 4 Then, we find the average of the squared differences: (4+1+0+1+4)/5 = 2 Therefore, the variance of the given data set is 2. Answer is correct.
Pregunta 40 Informe
A body of mass 10kg moving with a velocity of 5\(ms^{-1}\) collides with another body of mass 15kg moving in the same direction as the first with a velocity of 2\(ms^{-1}\). After collision, the two bodies move together with a common velocity v\(ms^{-1}\).
Detalles de la respuesta
We can use the law of conservation of momentum to solve this problem. According to the law, the total momentum of the system before the collision is equal to the total momentum after the collision. Before collision: - Body 1 mass = 10kg, velocity = 5\(ms^{-1}\), momentum = 50 kg\(ms^{-1}\) - Body 2 mass = 15kg, velocity = 2\(ms^{-1}\), momentum = 30 kg\(ms^{-1}\) - Total momentum before collision = 50 + 30 = 80 kg\(ms^{-1}\) After collision: - Total mass = 10 + 15 = 25kg - Let v be the common velocity of the two bodies after the collision - Total momentum after collision = 25v Equating the two momenta, we get: 80 = 25v v = 80/25 = 3.2 Therefore, the common velocity of the two bodies after the collision is 3.2\(ms^{-1}\). Answer: (a) 3.2
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