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1942 Paper 2 Q201
D: 1500.0 B: 1500.0

Solve the set of equations: \begin{align*} x + y + \lambda z &= 2, \\ x - 3y + 7z &= 0, \\ \lambda x + 7y - 8z &= 5, \end{align*} for general values of \(\lambda\). Shew that there is a value of \(\lambda\) for which the equations have an infinite number of solutions, and give a formula for these solutions. Determine also the value of \(\lambda\) for which these equations have no finite solution.

1942 Paper 2 Q202
D: 1500.0 B: 1500.0

The sum of two roots of the equation \[ x^4 - 8x^3 + 19x^2 + 4\lambda x + 2 = 0 \] is equal to the sum of the other two. Determine the value of \(\lambda\) and solve the equation.

1942 Paper 2 Q203
D: 1500.0 B: 1500.0

Sketch the curve \[ y = x^2 / (x^2 + 3x + 2). \] By means of the line \(y+8=m(x+1)\), or otherwise, find the number of real roots of the equation \[ m(x+1)^2(x+2) = (3x+4)^2, \] when \(m\) is a real constant which is (i) positive, (ii) negative.

1942 Paper 2 Q204
D: 1500.0 B: 1500.0

Prove that the geometric mean of \(n\) positive numbers does not exceed their arithmetic mean. Prove that, if \(p\) and \(q\) are positive integers, \[ \sin^{2p}\theta \cos^{2q}\theta \le \frac{p^p q^q}{(p+q)^{p+q}}. \]

1942 Paper 2 Q205
D: 1500.0 B: 1500.0

Express \(\tan 5\theta\) in terms of \(\tan\theta\). (If a general formula is quoted, it must be proved.) Prove that the roots of the equation \[ t^5 - 5pt^4 - 10t^3 + 10pt^2 + 5t - p = 0, \] where \(p\) is real, are all real and distinct. Evaluate \(\tan \frac{\pi}{20}\).

1942 Paper 2 Q206
D: 1500.0 B: 1500.0

State and prove De Moivre's theorem for \((\cos\theta + i\sin\theta)^n\), when \(n\) is (i) a positive integer, (ii) a negative integer, (iii) a fraction of the form \(p/q\), where \(p,q\) are integers. Express \((1+i)^n\) in the form \(A+iB\), where \(n\) is a positive integer and \(A, B\) are real.

1942 Paper 2 Q207
D: 1500.0 B: 1500.0

Sketch the curve \[ xy = x^3 + y^3, \] and find (i) the radii of curvature at the origin of coordinates, (ii) the area of the loop.

1942 Paper 2 Q208
D: 1500.0 B: 1500.0

Find the indefinite integrals \[ \int \left( \frac{1+x}{1-x} \right)^{\frac{1}{2}} dx, \quad \int \cos^3 3x dx, \quad \int \tan^{-1} x dx. \] Evaluate \[ \int_0^1 \frac{dx}{(1+x^2)^{\frac{3}{2}} - x}. \]

1942 Paper 2 Q209
D: 1500.0 B: 1500.0

Find the values of \(x\) for which the function \(e^{mx} \cos 3x\), where \(m\) may be positive or negative, has a maximum or a minimum value, and distinguish between them.

1942 Paper 2 Q210
D: 1500.0 B: 1500.0

If \(f(x,y)\) is a function of \(x,y\) which takes the form \(g(u,v)\) when \(x,y\) are transformed by the relations \(x=\phi(u,v), y=\psi(u,v)\), prove that, in the usual notation, \[ \frac{\partial g}{\partial u} = \frac{\partial f}{\partial x}\frac{\partial \phi}{\partial u} + \frac{\partial f}{\partial y}\frac{\partial \psi}{\partial u}. \] If \(f(x,y)\) is a function of \(x,y\), and \(x,y\) are functions of \(t\) defined by the relations \(u(x,t)=0, v(y,t)=0\), and if \(f(x,y)\), when expressed as a function of \(t\), takes the form \(g(t)\), prove that \[ \frac{dg}{dt} = - \frac{ \left( \frac{\partial f}{\partial x}\frac{\partial u}{\partial t} \frac{\partial v}{\partial y} + \frac{\partial f}{\partial y} \frac{\partial v}{\partial t} \frac{\partial u}{\partial x} \right) }{ \frac{\partial u}{\partial x} \frac{\partial v}{\partial y} }. \]