Question 1
(a) [2 marks]
- M1: Apply Vieta's formulas to \(2x^2 + 6x + 7 = 0\)
- A1: \(a + b = -3\) and \(ab = 3.5\) (or \(\frac{7}{2}\))
(b) [5 marks]
- M1: Find \(a^2 - 1 + b^2 - 1 = (a+b)^2 - 2ab - 2\)
- M1: Calculate \((a+b)^2 - 2ab - 2 = 9 - 7 - 2 = 0\)
- M1: Find \((a^2-1)(b^2-1) = a^2b^2 - a^2 - b^2 + 1\)
- M1: Calculate \(a^2b^2 - (a^2 + b^2) + 1 = 12.25 - 7 + 1 = 6.25\)
- A1: Quadratic equation is \(4x^2 - 25 = 0\) (or equivalent with integer coefficients)
(c) [2 marks]
- M1: Use roots of quadratic from part (b)
- A1: \(a^2 = \frac{5}{2}\) and \(b^2 = \frac{5}{2}\) (or \(a^2 = 2.5\), \(b^2 = 2.5\))
Question 2
(a) [1 mark]
- B1: The integrand has a singularity (vertical asymptote) at \(x = 0\) within the interval of integration
(b) [4 marks]
- M1: Set up limit: \(\lim_{\epsilon \to 0^+} \int_{\epsilon}^{4} (4x - 4)x^{-1.5} \, dx\)
- M1: Integrate to get \(\left[-8x^{0.5} - 8x^{-0.5}\right]_{\epsilon}^{4}\)
- M1: Evaluate at limits
- DM1: Take limit as \(\epsilon \to 0^+\)
- A1: The integral does not have a finite value (or explain divergence to \(-\infty\))
Question 3
(a) [3 marks]
- M1: Rationalize \(\frac{3}{2+i}\) by multiplying by \(\frac{2-i}{2-i}\)
- M1: Calculate numerator and denominator
- A1: \((2+i)^3 = 2 + 11i\) (expressed in form \(2 + bi\) where \(b = 11\))
(b)(i) [4 marks]
- M1: Substitute \(z = 2 + i\) into \(z^3 + pz + q = 0\)
- M1: Calculate \((2+i)^3 = 2 + 11i\)
- M1: Set up equation \((2 + 11i) + p(2+i) + q = 0\)
- M1: Equate real and imaginary parts
- A1: \(p = -11\) and \(q = -50\)
(b)(ii) [2 marks]
- M1: Use that \(2-i\) is also a root (complex conjugate pair)
- A1: Quadratic factor is \(z^2 - 4z + 5\) (or equivalent)
(b)(iii) [2 marks]
- M1: Divide \(z^3 - 11z - 50\) by \(z^2 - 4z + 5\)
- A1: Real root is \(z = -2\)
Question 4
(a) [5 marks]
- M1: Solve \(\sin(3x + 45°) = \frac{1}{2}\)
- M1: Identify general angles: \(3x + 45° = 30° + 360°n\) or \(3x + 45° = 150° + 360°n\)
- M1: Rearrange to find \(x\)
- A1: \(x = -5° + 120°n\) or \(x = 35° + 120°n\)
- A1: Complete general solution stated clearly
(b) [1 mark]
- A1: Solution closest to \(200°\) is \(x = 155°\) (or appropriate value from general solution)
Question 5
(a) [4 marks]
- M1: Set up matrix equation \(\begin{pmatrix} -2 & c \\ d & 3 \end{pmatrix} \begin{pmatrix} 5 \\ 2 \end{pmatrix} = \begin{pmatrix} -2 \\ 1 \end{pmatrix}\)
- M1: Form equations \(-10 + 2c = -2\) and \(5d + 6 = 1\)
- A1: \(c = 4\)
- A1: \(d = -1\)
(b)(i) [2 marks]
- M1: Calculate successive powers of \(B\)
- A1: \(B^4 = 4I\) (so \(k = 4\))
(b)(ii) [5 marks]
- B1: Identify that \(B\) represents a rotation (by \(45°\) counterclockwise)
- B1: Identify that \(B\) represents a scaling (by factor \(\sqrt{2}\))
- A1: Described as rotation by \(45°\) combined with enlargement scale factor \(\sqrt{2}\)
- A1: Clear description of order and combination
- A1: Centre of rotation stated (origin) if required
(b)(iii) [2 marks]
- M1: Use \(B^{17} = B^{16} \cdot B = (B^4)^4 \cdot B = (4I)^4 \cdot B = 256I \cdot B\)
- A1: \(B^{17} = 256B = \begin{pmatrix} 128\sqrt{2} & 128\sqrt{2} \\ -128\sqrt{2} & 128\sqrt{2} \end{pmatrix}\) (or equivalent form)
Question 6
(a) [2 marks]
- B1: Sketch of hyperbola with correct shape and orientation
- A1: State intercepts: \((\pm 3, 0)\); no \(y\)-intercepts
(b) [3 marks]
- M1: Apply translation to get equation of \(C_2\)
- M1: Use condition that \(C_2\) passes through origin
- A1: Asymptotes are \(y = \pm \frac{4}{3}(x + 3)\) (or equivalent form)
Question 7
(a)(i) [2 marks]
- M1: Evaluate \(f(39)\) and \(f(40)\) for \(f(x) = 2x^3 + 5x^2 + 3x - 132000\)
- A1: Show sign change confirms \(39 < a < 40\)
(a)(ii) [3 marks]
- M1: Apply Newton-Raphson: \(x_2 = x_1 - \frac{f(x_1)}{f'(x_1)}\) with \(x_1 = 40\)
- M1: Calculate \(f(40)\) and \(f'(40) = 6x^2 + 10x + 3\)
- A1: \(x_2 = 39.49\) (to 2 d.p.)
(b) [5 marks]
- M1: Expand \(2r(3r + 2) = 6r^2 + 4r\)
- M1: Write as $\Sigma 6r^2 + 4\Sigma