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AQA Level 2 Further Maths Paper 1 (Non-Calculator) 2024

๐Ÿ“ Guidance

  • Paper Type: Non-Calculator (Show all working clearly)
  • Total Questions: 23
  • Format: Interactive Worksheets with Pedagogical Solutions
  • Notation: Standard MathJax \( x^2 \) notation used throughout

Question 1 (2 marks)

Work out the value of \( \sqrt{\frac{t}{20}} \) where \( t = 2.42 \times 10^3 \)

๐ŸŽ“ Worked Solution

Step 1: Convert standard form to an ordinary number

๐Ÿ’ก Why we do this: Working with ordinary integers is often easier for division than working with standard form directly, especially when we need to find a square root later.

โœ Working:

\[ t = 2.42 \times 1000 = 2420 \]
Step 2: Substitute and simplify the fraction

๐Ÿ’ก Strategy: Place the value of \( t \) into the expression and perform the division before taking the square root.

โœ Working:

\[ \frac{t}{20} = \frac{2420}{20} \]

Cancel the zeros:

\[ \frac{242}{2} = 121 \]
Step 3: Calculate the square root

๐Ÿ’ก Verification: We recognize 121 as a square number.

โœ Working:

\[ \sqrt{121} = 11 \]

โœ“ (M1 for 121, A1 for 11)

๐Ÿ Final Answer:

11

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Question 2 (1 mark)

Factorise \( x^2 – y^2 \)

๐ŸŽ“ Worked Solution

Step 1: Identify the algebraic structure

๐Ÿ’ก What this tells us: This is a standard identity known as the “Difference of Two Squares”. It always follows the pattern \( a^2 – b^2 = (a-b)(a+b) \).

โœ Working:

\[ x^2 – y^2 = (x – y)(x + y) \]

โœ“ (B1)

๐Ÿ Final Answer:

\( (x – y)(x + y) \)

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Question 3 (1 mark)

The \( n \)th term of a sequence is \( \frac{3n + 4}{n} \)

Circle the limiting value of \( \frac{3n + 4}{n} \) as \( n \to \infty \)

   1        3        4        7

๐ŸŽ“ Worked Solution

Step 1: Simplify the expression

๐Ÿ’ก Why we do this: To see what happens as \( n \) gets very large, it helps to split the fraction into separate terms.

โœ Working:

\[ \frac{3n + 4}{n} = \frac{3n}{n} + \frac{4}{n} = 3 + \frac{4}{n} \]
Step 2: Apply the limit

๐Ÿ’ก What this tells us: As \( n \) becomes infinitely large (\( n \to \infty \)), the fraction \( \frac{4}{n} \) becomes closer and closer to 0.

โœ Working:

\[ \text{Limit} = 3 + 0 = 3 \]

โœ“ (B1)

๐Ÿ Final Answer:

3

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Question 4 (2 marks)

The equations of two straight lines are

\( y – 3x = 4 \)   and   \( 6y = 18x – 5 \)

Show that the lines are parallel.

๐ŸŽ“ Worked Solution

Step 1: Understand the condition for parallel lines

๐Ÿ’ก Core Principle: Parallel lines must have the same gradient (\( m \)). To find the gradient, we rearrange both equations into the form \( y = mx + c \).

Step 2: Rearrange the first equation

โœ Working:

\[ y – 3x = 4 \] \[ y = 3x + 4 \]

Gradient \( m_1 = 3 \)

Step 3: Rearrange the second equation

โœ Working:

\[ 6y = 18x – 5 \]

Divide all terms by 6:

\[ y = \frac{18}{6}x – \frac{5}{6} \] \[ y = 3x – \frac{5}{6} \]

Gradient \( m_2 = 3 \)

Step 4: Conclusion

โœ Working:

Since \( m_1 = 3 \) and \( m_2 = 3 \), the gradients are equal.

Therefore, the lines are parallel.

โœ“ (M1 for rearranging, A1 for conclusion)

๐Ÿ Final Answer:

Both gradients are 3, so lines are parallel.

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Question 5 (3 marks)

\( y = \frac{4x^3 + x^7}{x^4} \)

Work out \( \frac{dy}{dx} \)

๐ŸŽ“ Worked Solution

Step 1: Simplify the expression before differentiating

๐Ÿ’ก Strategy: It is much easier to differentiate separate terms of the form \( ax^n \) than a fraction. We divide each term in the numerator by \( x^4 \).

โœ Working:

\[ y = \frac{4x^3}{x^4} + \frac{x^7}{x^4} \] \[ y = 4x^{-1} + x^3 \]

โœ“ (M1 for correct term simplified)

Step 2: Differentiate term by term

๐Ÿ’ก How: Use the power rule: multiply by the power, reduce the power by 1.

  • For \( 4x^{-1} \): \( -1 \times 4x^{-2} = -4x^{-2} \)
  • For \( x^3 \): \( 3 \times x^2 = 3x^2 \)

โœ Working:

\[ \frac{dy}{dx} = -4x^{-2} + 3x^2 \]

โœ“ (A1 for one term correct, A1 for both)

๐Ÿ Final Answer:

\( \frac{dy}{dx} = -4x^{-2} + 3x^2 \) or \( -\frac{4}{x^2} + 3x^2 \)

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Question 6 (3 marks)

Points \( A(-12, 1) \) and \( B(12, -1) \) lie on a circle.

\( AB \) is a diameter of the circle.

Work out the equation of the circle.

๐ŸŽ“ Worked Solution

Step 1: Find the centre of the circle

๐Ÿ’ก Why we do this: The centre of the circle is the midpoint of the diameter \( AB \).

โœ Working:

\[ \text{Centre} = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right) \] \[ \text{Centre} = \left( \frac{-12 + 12}{2}, \frac{1 + (-1)}{2} \right) \] \[ \text{Centre} = (0, 0) \]

โœ“ (B1)

Step 2: Find the radius squared (\( r^2 \))

๐Ÿ’ก How: The radius is the distance from the centre (0,0) to point A (or B). We use Pythagoras’ theorem.

โœ Working:

\[ r^2 = (x – 0)^2 + (y – 0)^2 \]

Using point A(-12, 1):

\[ r^2 = (-12)^2 + 1^2 \] \[ r^2 = 144 + 1 = 145 \]

โœ“ (M1)

Step 3: Write the equation

๐Ÿ’ก Formula: The equation of a circle with centre (0,0) is \( x^2 + y^2 = r^2 \).

โœ Working:

\[ x^2 + y^2 = 145 \]

โœ“ (B1)

๐Ÿ Final Answer:

\( x^2 + y^2 = 145 \)

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Question 7 (3 marks)

A point \( P(x, y) \) is transformed using the transformation represented by \( \begin{pmatrix} 4 & 0 \\ -2 & 3 \end{pmatrix} \)

The image of \( P \) is \( (-8, 7) \)

Work out the values of \( x \) and \( y \).

๐ŸŽ“ Worked Solution

Step 1: Set up the matrix multiplication

๐Ÿ’ก What this tells us: Multiplying the matrix by the point vector gives the image vector.

โœ Working:

\[ \begin{pmatrix} 4 & 0 \\ -2 & 3 \end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix} -8 \\ 7 \end{pmatrix} \]

โœ“ (M1)

Step 2: Form equations from rows

โœ Working:

Top row: \( 4x + 0y = -8 \)

Bottom row: \( -2x + 3y = 7 \)

โœ“ (M1)

Step 3: Solve the equations

โœ Working:

From top row:

\[ 4x = -8 \implies x = -2 \]

Substitute \( x = -2 \) into bottom row:

\[ -2(-2) + 3y = 7 \] \[ 4 + 3y = 7 \] \[ 3y = 3 \implies y = 1 \]

โœ“ (A1)

๐Ÿ Final Answer:

\( x = -2, \quad y = 1 \)

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Question 8 (3 marks)

Solve by factorising \( 2x^3 – 9x^2 – 5x = 0 \)

๐ŸŽ“ Worked Solution

Step 1: Factor out the common term \( x \)

๐Ÿ’ก Strategy: Always check for a common factor first. Here, every term contains \( x \).

โœ Working:

\[ x(2x^2 – 9x – 5) = 0 \]

โœ“ (M1)

Step 2: Factorise the quadratic part

๐Ÿ’ก How: We need to factorise \( 2x^2 – 9x – 5 \). We need numbers that multiply to \( 2 \times -5 = -10 \) and add to \( -9 \). These are \( -10 \) and \( 1 \).

โœ Working:

\[ 2x^2 – 10x + x – 5 \] \[ 2x(x – 5) + 1(x – 5) \] \[ (2x + 1)(x – 5) \]

So the full equation is:

\[ x(2x + 1)(x – 5) = 0 \]

โœ“ (M1)

Step 3: Find the solutions

๐Ÿ’ก Check: Set each bracket to zero.

โœ Working:

\( x = 0 \)

\( 2x + 1 = 0 \implies x = -0.5 \)

\( x – 5 = 0 \implies x = 5 \)

โœ“ (A1)

๐Ÿ Final Answer:

\( x = 0, \quad x = -0.5, \quad x = 5 \)

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Question 9 (3 marks)

\( ABCDEFGH \) is a cuboid.

Work out the length \( AG \).

A B C D E F G H 3 cm 12 cm 4 cm

๐ŸŽ“ Worked Solution

Step 1: Identify the method (3D Pythagoras)

๐Ÿ’ก Core Principle: To find the space diagonal \( AG \) of a cuboid, we use the 3D Pythagoras formula: \( d = \sqrt{x^2 + y^2 + z^2} \).

Step 2: Substitute the dimensions

โœ Working:

Length = 4 cm, Width = 3 cm, Height = 12 cm

\[ AG = \sqrt{4^2 + 3^2 + 12^2} \] \[ AG = \sqrt{16 + 9 + 144} \]

โœ“ (M1)

Step 3: Calculate the result

โœ Working:

\[ AG = \sqrt{169} \] \[ AG = 13 \]

โœ“ (M1 for 169, A1 for 13)

๐Ÿ Final Answer:

13 cm

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Question 10 (5 marks)

A function \( f \) is given by

\( f(x) = -\frac{1}{2}x + 21 \quad \text{for } 0 \le x \le 2 \)

\( f(x) = ax^2 + bx \quad \text{for } 2 < x \le 6 \)

A sketch of \( y = f(x) \) is shown.

x y O P Q (6, 12)

Work out the values of \( a \) and \( b \).

๐ŸŽ“ Worked Solution

Step 1: Find the coordinates of P

๐Ÿ’ก Analysis: Point P is at \( x = 2 \). Since the function is continuous, the value of the first part \( f(x) = -\frac{1}{2}x + 21 \) at \( x=2 \) gives the y-coordinate of P.

โœ Working:

\[ y = -\frac{1}{2}(2) + 21 \] \[ y = -1 + 21 = 20 \]

So P is \( (2, 20) \).

โœ“ (M1 for P coordinates)

Step 2: Set up equations for \( a \) and \( b \)

๐Ÿ’ก Strategy: The quadratic part \( f(x) = ax^2 + bx \) passes through P(2, 20) and Q(6, 12). We form two simultaneous equations.

โœ Working:

At P(2, 20):

\[ a(2)^2 + b(2) = 20 \] \[ 4a + 2b = 20 \quad \text{(Divide by 2)} \rightarrow \quad 2a + b = 10 \quad \text{(1)} \]

At Q(6, 12):

\[ a(6)^2 + b(6) = 12 \] \[ 36a + 6b = 12 \quad \text{(Divide by 6)} \rightarrow \quad 6a + b = 2 \quad \text{(2)} \]

โœ“ (M1, M1)

Step 3: Solve the simultaneous equations

โœ Working:

Subtract equation (1) from equation (2):

\[ (6a + b) – (2a + b) = 2 – 10 \] \[ 4a = -8 \] \[ a = -2 \]

Substitute \( a = -2 \) into equation (1):

\[ 2(-2) + b = 10 \] \[ -4 + b = 10 \] \[ b = 14 \]

โœ“ (A1, A1)

๐Ÿ Final Answer:

\( a = -2, \quad b = 14 \)

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Question 11 (6 marks)

(a) \( (3x – 7) \) is a factor of \( 3x^3 – 4x^2 – 13x + 14 \)

Work out the other two linear factors.

(b) \( (x – 2) \) is a factor of \( ax^4 – 3ax^3 + 5x – 22 \)

Work out the value of \( a \).

๐ŸŽ“ Worked Solution

Part (a): Polynomial Division

๐Ÿ’ก Strategy: Since \( (3x-7) \) is a factor, we can divide the cubic by it to find the remaining quadratic factor.

โœ Working:

Compare coefficients or use division:

\[ (3x – 7)(Ax^2 + Bx + C) = 3x^3 – 4x^2 – 13x + 14 \]
  • \( 3x \times Ax^2 = 3x^3 \implies A = 1 \)
  • \( -7 \times C = 14 \implies C = -2 \)

Checking \( x^2 \) term: \( (3x)(Bx) + (-7)(x^2) = -4x^2 \)

\[ 3B – 7 = -4 \] \[ 3B = 3 \implies B = 1 \]

The quadratic factor is \( x^2 + x – 2 \).

โœ“ (M1)

Part (a): Factorise the quadratic

โœ Working:

\[ x^2 + x – 2 = (x + 2)(x – 1) \]

โœ“ (A1)

Part (b): Factor Theorem

๐Ÿ’ก Core Principle: If \( (x – 2) \) is a factor, then substituting \( x = 2 \) into the polynomial must give 0.

โœ Working:

\[ f(2) = 0 \] \[ a(2)^4 – 3a(2)^3 + 5(2) – 22 = 0 \] \[ 16a – 3a(8) + 10 – 22 = 0 \] \[ 16a – 24a – 12 = 0 \] \[ -8a = 12 \] \[ a = \frac{12}{-8} = -1.5 \]

โœ“ (M1, M1, A1)

๐Ÿ Final Answer:

(a) \( (x+2) \) and \( (x-1) \)

(b) \( a = -1.5 \)

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Question 12 (3 marks)

In triangle \( ABC \), \( \cos A = \frac{3}{4} \)

Work out the length \( BC \).

A B C 12 cm 10 cm

๐ŸŽ“ Worked Solution

Step 1: Identify the rule

๐Ÿ’ก Strategy: We have two sides and the included angle (or its cosine). This is a job for the Cosine Rule: \( a^2 = b^2 + c^2 – 2bc \cos A \).

Step 2: Substitute values

โœ Working:

\[ BC^2 = 12^2 + 10^2 – 2(12)(10)\left(\frac{3}{4}\right) \] \[ BC^2 = 144 + 100 – 240\left(\frac{3}{4}\right) \]

โœ“ (M1)

Step 3: Calculate

โœ Working:

\[ 240 \div 4 = 60 \implies 60 \times 3 = 180 \] \[ BC^2 = 244 – 180 \] \[ BC^2 = 64 \] \[ BC = \sqrt{64} = 8 \]

โœ“ (M1, A1)

๐Ÿ Final Answer:

8 cm

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Question 13 (4 marks)

A garden patio is made from two rectangles. All lengths are in metres.

7 8 x x – 3

The area of the patio is less than 51 mยฒ.

Work out the range of possible values of \( x \).

Give your answer in the form \( a < x < b \) where \( a \) and \( b \) are both integers.

๐ŸŽ“ Worked Solution

Step 1: Express the area in terms of x

๐Ÿ’ก Strategy: Split the L-shape into two rectangles. We can split it vertically.

  • Rectangle 1 (Left): Width 7, Height \( x \). Area = \( 7x \).
  • Rectangle 2 (Right): Width 8, Height \( x – 3 \). Area = \( 8(x-3) \).

โœ Working:

\[ \text{Total Area} = 7x + 8(x – 3) \] \[ = 7x + 8x – 24 \] \[ = 15x – 24 \]

โœ“ (M1)

Step 2: Form and solve the inequality

โœ Working:

\[ 15x – 24 < 51 \] \[ 15x < 75 \] \[ x < 5 \]

โœ“ (M1)

Step 3: Consider geometric constraints

๐Ÿ’ก Critical Check: A length cannot be zero or negative. The shortest vertical side is \( x – 3 \).

โœ Working:

\[ x – 3 > 0 \] \[ x > 3 \]

โœ“ (B1)

๐Ÿ Final Answer:

\( 3 < x < 5 \)

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Question 14 (4 marks)

(a) Write \( 2x^2 – 16x + 7 \) in the form \( k(x + m)^2 + n \) where \( k, m \) and \( n \) are integers.

(b) Solve \( (x – 1)^2 – 5 = 0 \)

๐ŸŽ“ Worked Solution

Part (a): Completing the Square

๐Ÿ’ก Strategy: Factor out the coefficient of \( x^2 \) from the first two terms first.

โœ Working:

\[ 2(x^2 – 8x) + 7 \]

Complete the square for \( x^2 – 8x \): \( (x-4)^2 – 16 \)

\[ 2[(x – 4)^2 – 16] + 7 \] \[ 2(x – 4)^2 – 32 + 7 \] \[ 2(x – 4)^2 – 25 \]

โœ“ (M1, M1, A1)

Part (b): Solving

โœ Working:

\[ (x – 1)^2 = 5 \] \[ x – 1 = \pm\sqrt{5} \] \[ x = 1 \pm \sqrt{5} \]

โœ“ (B1)

๐Ÿ Final Answer:

(a) \( 2(x – 4)^2 – 25 \)

(b) \( 1 \pm \sqrt{5} \)

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Question 15 (3 marks)

(a) Matrix \( M \) represents a reflection in the line \( y = -x \)

Write down matrix \( M \)

(b) \( N = \begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix} \)

Describe geometrically the single transformation represented by \( N^2 \)

๐ŸŽ“ Worked Solution

Part (a): Reflection Matrix

๐Ÿ’ก Analysis: The line \( y = -x \) swaps coordinates and changes signs. \( (1, 0) \to (0, -1) \) and \( (0, 1) \to (-1, 0) \).

โœ Working:

\[ M = \begin{pmatrix} 0 & -1 \\ -1 & 0 \end{pmatrix} \]

โœ“ (B1)

Part (b): Calculate \( N^2 \)

โœ Working:

\[ N^2 = \begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix} \begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix} \] \[ = \begin{pmatrix} (0)(0) + (1)(-1) & (0)(1) + (1)(0) \\ (-1)(0) + (0)(-1) & (-1)(1) + (0)(0) \end{pmatrix} \] \[ = \begin{pmatrix} -1 & 0 \\ 0 & -1 \end{pmatrix} \]

โœ“ (M1)

Part (b): Describe Transformation

๐Ÿ’ก Interpretation: The matrix \( \begin{pmatrix} -1 & 0 \\ 0 & -1 \end{pmatrix} \) changes the sign of both x and y. This corresponds to a 180ยฐ rotation.

โœ Working:

Rotation 180ยฐ about the origin (or enlargement scale factor -1).

โœ“ (A1)

๐Ÿ Final Answer:

(a) \( \begin{pmatrix} 0 & -1 \\ -1 & 0 \end{pmatrix} \)

(b) Rotation 180ยฐ about the origin

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Question 16 (4 marks)

\( A, B, C \) and \( D \) are points on a circle, centre \( O \).

Angle \( OBC \) : Angle \( ODC = 5 : 3 \)

O A B C D 52ยฐ

Work out the size of angle \( OBC \).

You must show your working.

๐ŸŽ“ Worked Solution

Step 1: Use Circle Theorems

๐Ÿ’ก Strategy: We need to find the angles in the quadrilateral.
1. Since \( ABCD \) is a cyclic quadrilateral, opposite angles add to 180ยฐ.
2. Angle at centre is double the angle at the circumference.

โœ Working:

Angle \( BCD = 180ยฐ – 52ยฐ = 128ยฐ \)

Step 2: Set up algebraic expression for angles

๐Ÿ’ก Insight: \( OB \) and \( OD \) are radii, so triangles \( OBC \) and \( ODC \) are isosceles. This means angle \( OCB = \) angle \( OBC \) and angle \( OCD = \) angle \( ODC \).

The question gives the ratio \( OBC : ODC = 5 : 3 \). Let’s use \( x \).

โœ Working:

Let Angle \( OBC = 5x \)

Let Angle \( ODC = 3x \)

Therefore, Angle \( OCB = 5x \) and Angle \( OCD = 3x \).

The total angle \( BCD \) is the sum of these:

\[ 5x + 3x = 128 \] \[ 8x = 128 \]

โœ“ (M1)

Step 3: Solve for angle OBC

โœ Working:

\[ x = \frac{128}{8} = 16 \]

We need Angle \( OBC \) which is \( 5x \):

\[ 5 \times 16 = 80^{\circ} \]

โœ“ (A1)

๐Ÿ Final Answer:

80ยฐ

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Question 17 (3 marks)

Show that \( \frac{21x}{3x^2 – 2x – 8} – \frac{7}{x – 2} \) simplifies to \( \frac{k}{3x^2 – 2x – 8} \)

where \( k \) is an integer.

๐ŸŽ“ Worked Solution

Step 1: Factorise the denominator

๐Ÿ’ก Strategy: To subtract fractions, we need a common denominator. Let’s factorise \( 3x^2 – 2x – 8 \) first.

โœ Working:

We need numbers that multiply to \( 3 \times -8 = -24 \) and add to \( -2 \). (-6 and 4).

\[ 3x^2 – 6x + 4x – 8 \] \[ 3x(x – 2) + 4(x – 2) \] \[ (3x + 4)(x – 2) \]

โœ“ (M1)

Step 2: Convert to common denominator

โœ Working:

The expression becomes:

\[ \frac{21x}{(3x + 4)(x – 2)} – \frac{7}{x – 2} \]

Multiply top and bottom of the second fraction by \( (3x + 4) \):

\[ \frac{21x}{(3x + 4)(x – 2)} – \frac{7(3x + 4)}{(3x + 4)(x – 2)} \]
Step 3: Combine and simplify

โœ Working:

\[ \text{Numerator} = 21x – 7(3x + 4) \] \[ = 21x – 21x – 28 \] \[ = -28 \]

So the fraction is:

\[ \frac{-28}{3x^2 – 2x – 8} \]

โœ“ (M1, A1)

๐Ÿ Final Answer:

\( k = -28 \)

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Question 18 (4 marks)

Rationalise the denominator and simplify fully:

\[ \frac{3\sqrt{5} + \sqrt{3}}{\sqrt{5} – \sqrt{3}} \]

๐ŸŽ“ Worked Solution

Step 1: Multiply by the conjugate

๐Ÿ’ก Strategy: To remove surds from the bottom, multiply the numerator and denominator by \( \sqrt{5} + \sqrt{3} \).

โœ Working:

\[ \frac{3\sqrt{5} + \sqrt{3}}{\sqrt{5} – \sqrt{3}} \times \frac{\sqrt{5} + \sqrt{3}}{\sqrt{5} + \sqrt{3}} \]

โœ“ (M1)

Step 2: Expand the numerator and denominator

โœ Working:

Denominator:

\[ (\sqrt{5} – \sqrt{3})(\sqrt{5} + \sqrt{3}) = 5 – 3 = 2 \]

Numerator:

\[ (3\sqrt{5} + \sqrt{3})(\sqrt{5} + \sqrt{3}) \] \[ = 3(5) + 3\sqrt{15} + \sqrt{15} + 3 \] \[ = 15 + 4\sqrt{15} + 3 \] \[ = 18 + 4\sqrt{15} \]

โœ“ (M1, M1)

Step 3: Simplify the fraction

โœ Working:

\[ \frac{18 + 4\sqrt{15}}{2} \] \[ = 9 + 2\sqrt{15} \]

โœ“ (A1)

๐Ÿ Final Answer:

\( 9 + 2\sqrt{15} \)

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Question 19 (5 marks)

The equation of a curve is \( y = x^3 – 3x^2 + 5 \)

Work out the stationary points of the curve and determine their nature.

You must show your working.

๐ŸŽ“ Worked Solution

Step 1: Differentiate and set to zero

๐Ÿ’ก Why we do this: Stationary points occur where the gradient (\( \frac{dy}{dx} \)) is zero.

โœ Working:

\[ \frac{dy}{dx} = 3x^2 – 6x \]

Set to 0:

\[ 3x^2 – 6x = 0 \] \[ 3x(x – 2) = 0 \]

So, \( x = 0 \) or \( x = 2 \).

โœ“ (M1, A1)

Step 2: Find y-coordinates

โœ Working:

When \( x = 0 \):

\[ y = 0^3 – 3(0)^2 + 5 = 5 \implies (0, 5) \]

When \( x = 2 \):

\[ y = 2^3 – 3(2)^2 + 5 \] \[ y = 8 – 12 + 5 = 1 \implies (2, 1) \]
Step 3: Determine nature using the second derivative

๐Ÿ’ก How: We find \( \frac{d^2y}{dx^2} \). If it’s positive, it’s a minimum. If negative, it’s a maximum.

โœ Working:

\[ \frac{d^2y}{dx^2} = 6x – 6 \]

At \( x = 0 \):

\[ 6(0) – 6 = -6 \quad (< 0 \text{ Maximum}) \]

At \( x = 2 \):

\[ 6(2) – 6 = 6 \quad (> 0 \text{ Minimum}) \]

โœ“ (M1, A1)

๐Ÿ Final Answer:

(0, 5) Maximum

(2, 1) Minimum

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Question 20 (4 marks)

Here is the graph of \( y = -x^2 + 3x + 6 \) for \( -2 \le x \le 5 \)

x y O 1 2 3 4 5 -1 -2

By drawing a suitable straight line, work out approximate solutions to

\[ x^2 – \frac{7}{2}x – 3 = 0 \]

๐ŸŽ“ Worked Solution

Step 1: Manipulate the equation to match the graph

๐Ÿ’ก Strategy: We have the graph of \( y = -x^2 + 3x + 6 \). We need to solve \( x^2 – 3.5x – 3 = 0 \).
Rearrange the target equation to look like the graph equation.

โœ Working:

Target: \( x^2 – 3.5x – 3 = 0 \)

Multiply by -1: \( -x^2 + 3.5x + 3 = 0 \)

We want \( -x^2 + 3x + 6 \) on the LHS.

Add \( -0.5x \) and \( +3 \) to the equation to adjust coefficients:

\[ (-x^2 + 3.5x + 3) + (-0.5x + 3) = 0 + (-0.5x + 3) \] \[ -x^2 + 3x + 6 = -0.5x + 3 \]

โœ“ (B2 for identifying line)

Step 2: Identify the line to draw

๐Ÿ’ก Insight: The intersection of the curve \( y = -x^2 + 3x + 6 \) and the line \( y = -0.5x + 3 \) gives the solutions.

Draw line \( y = -0.5x + 3 \):

  • When \( x = 0, y = 3 \)
  • When \( x = 6, y = 0 \)

โœ Working:

Draw the straight line passing through (0, 3) and (4, 1).

โœ“ (M1 for drawing line)

Step 3: Read intersections

โœ Working:

The line intersects the curve at approx \( x = -0.7 \) and \( x = 4.2 \).

โœ“ (A1)

๐Ÿ Final Answer:

\( x \approx -0.7 \) and \( x \approx 4.2 \)

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Question 21 (5 marks)

\( (2^{x+3})^{4x+1} = 8^{x-1} \)

Work out the possible values of \( x \).

๐ŸŽ“ Worked Solution

Step 1: Express bases as powers of 2

๐Ÿ’ก Strategy: To solve exponential equations, get the same base on both sides. Note that \( 8 = 2^3 \).

โœ Working:

\[ \text{LHS} = 2^{(x+3)(4x+1)} \] \[ \text{RHS} = (2^3)^{x-1} = 2^{3(x-1)} \]

โœ“ (M1)

Step 2: Equate powers and expand

โœ Working:

\[ (x+3)(4x+1) = 3(x-1) \] \[ 4x^2 + x + 12x + 3 = 3x – 3 \] \[ 4x^2 + 13x + 3 = 3x – 3 \]

โœ“ (M1 for expansion)

Step 3: Solve the quadratic

โœ Working:

\[ 4x^2 + 10x + 6 = 0 \]

Divide by 2:

\[ 2x^2 + 5x + 3 = 0 \]

Factorise:

\[ (2x + 3)(x + 1) = 0 \]

Solutions:

\[ x = -1.5 \quad \text{or} \quad x = -1 \]

โœ“ (M1 for solving, A1 for answers)

๐Ÿ Final Answer:

\( x = -1.5 \) and \( x = -1 \)

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Question 22 (4 marks)

\( f(x) = \frac{3 \sin x \cos x + \sin^2 x}{12 \cos^2 x + 4 \sin x \cos x} \)

Simplify \( f(x) \) and hence solve \( f(x) = -\frac{\sqrt{3}}{4} \) for \( 90^{\circ} < x < 180^{\circ} \)

You must show your working.

๐ŸŽ“ Worked Solution

Step 1: Factorise numerator and denominator

๐Ÿ’ก Strategy: Look for common factors to simplify the fraction.

โœ Working:

Numerator: \( \sin x (3 \cos x + \sin x) \)

Denominator: \( 4 \cos x (3 \cos x + \sin x) \)

โœ“ (M1)

Step 2: Simplify to tan x

โœ Working:

Cancel \( (3 \cos x + \sin x) \):

\[ f(x) = \frac{\sin x}{4 \cos x} = \frac{1}{4} \tan x \]

โœ“ (M1)

Step 3: Solve the equation

โœ Working:

\[ \frac{1}{4} \tan x = -\frac{\sqrt{3}}{4} \] \[ \tan x = -\sqrt{3} \]

The reference angle where \( \tan \alpha = \sqrt{3} \) is \( 60^{\circ} \).

Since \( \tan \) is negative in the 2nd quadrant (\( 90 < x < 180 \)):

\[ x = 180^{\circ} – 60^{\circ} = 120^{\circ} \]

โœ“ (A1)

๐Ÿ Final Answer:

\( 120^{\circ} \)

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Question 23 (5 marks)

The \( n \)th term of a quadratic sequence is \( an^2 – 5n + c \) where \( a \) and \( c \) are integers.

The first four terms of the sequence are:

2    \( x \)    16    \( y \)

Work out the values of \( x \) and \( y \).

๐ŸŽ“ Worked Solution

Step 1: Use given terms to find a and c

๐Ÿ’ก Strategy: We know the 1st term (n=1) is 2, and the 3rd term (n=3) is 16. We can create simultaneous equations.

โœ Working:

For n=1 (Term = 2):

\[ a(1)^2 – 5(1) + c = 2 \] \[ a – 5 + c = 2 \implies a + c = 7 \quad \text{(1)} \]

For n=3 (Term = 16):

\[ a(3)^2 – 5(3) + c = 16 \] \[ 9a – 15 + c = 16 \implies 9a + c = 31 \quad \text{(2)} \]

โœ“ (M1, M1)

Step 2: Solve for a and c

โœ Working:

Subtract (1) from (2):

\[ 8a = 24 \implies a = 3 \]

Substitute into (1):

\[ 3 + c = 7 \implies c = 4 \]

The nth term rule is \( 3n^2 – 5n + 4 \).

โœ“ (M1)

Step 3: Calculate x and y

โœ Working:

Find x (n=2):

\[ x = 3(2)^2 – 5(2) + 4 \] \[ x = 12 – 10 + 4 = 6 \]

Find y (n=4):

\[ y = 3(4)^2 – 5(4) + 4 \] \[ y = 48 – 20 + 4 = 32 \]

โœ“ (A1, A1)

๐Ÿ Final Answer:

\( x = 6, \quad y = 32 \)

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