IB Maths Analysis & Approaches HL — Interactive Practice Paper 2
Paper 2 is the calculator-required paper — rewards students who can wield the GDC efficiently for systems, vector geometry, probability and calculus. Two modes: instant per-part feedback while you learn, or full timed exam simulation.
Consider the following system of three linear equations in three unknowns:
$$\begin{aligned} x + 2y - z &= 5 \\ 3x - y + 2z &= 8 \\ 4x + y + z &= 15 \end{aligned}$$
(a) Use your GDC (matrix RREF) to determine whether the system is consistent or inconsistent. Type consistent or inconsistent. [2]
Casio fx-CG50: MENU A (Equation) → Simultaneous → 3 unknowns.
(b) Find the values of $x$, $y$, $z$. Give as a comma-separated triple. [3]
(a) Coefficient matrix has determinant $\det\begin{pmatrix}1&2&-1\\3&-1&2\\4&1&1\end{pmatrix} = -14 \ne 0$, so a unique solution exists — the system is consistent. (b) Row-reducing the augmented matrix on the GDC yields the unique solution $\mathbf{(x, y, z) = (3, 2, 2)}$.
Question 2
6 marksHLGDC required
Vectors — angle between a line and a plane
The line $L$ has vector equation $$\mathbf{r} = \begin{pmatrix} 2 \\ 1 \\ 0 \end{pmatrix} + \lambda \begin{pmatrix} 1 \\ 2 \\ 2 \end{pmatrix}$$ and the plane $\Pi$ has Cartesian equation $3x - 4y = 10$.
(a) Write down the direction vector of $L$ and a normal vector of $\Pi$. Give each as a comma-separated triple. [2]
(b) Find the angle $\theta$ between $L$ and $\Pi$, in degrees, correct to one decimal place. [4]
(a) $\mathbf{d}_L = (1, 2, 2)$ and $\mathbf{n}_\Pi = (3, -4, 0)$. (b) $\mathbf{d} \cdot \mathbf{n} = 3 - 8 + 0 = -5$.
$|\mathbf{d}| = 3$, $|\mathbf{n}| = 5$.
$\sin\theta = \dfrac{|-5|}{3 \times 5} = \dfrac{1}{3}$.
$\theta = \arcsin(1/3) \approx \mathbf{19.5°}$. This is the acute angle between the line and the plane (IB convention).
Question 3
6 marksHLGDC required
Conditional Probability — independence and $P(G|T)$
At a pet shop, $G$ is the event that a customer buys a goldfish and $T$ is the event that a customer buys a tortoise. It is given that $P(G) = 0.3$, $P(T) = 0.4$, and $P(G' \cap T') = 0.42$.
(a) Find $P(G \cup T)$. [1]
(b) Find $P(G \cap T)$. [2]
(c) Are $G$ and $T$ independent? Type yes or no. [1]
(b) Evaluate the gradient at $x = 1$. Give the exact form as $a(1 + b\ln 3)$ and enter $a + b$ (both integers). [1]
(c) Find the exact equation of the tangent line at $x = 1$, in the form $y = mx + c$. Give $c$ exactly. [2]
(a) Product rule: $\dfrac{dy}{dx} = 3^x + x \cdot 3^x \ln 3 = 3^x(1 + x\ln 3)$, so $k = \mathbf{1}$. (b) At $x = 1$: $m = 3^1(1 + \ln 3) = 3(1 + \ln 3)$, so $a = 3, b = 3$ and $a + b = \mathbf{4}$. (c) Point: $(1, 3)$. Tangent: $y - 3 = 3(1 + \ln 3)(x - 1) \Rightarrow y = 3(1 + \ln 3)x - 3\ln 3$, so $c = \mathbf{-3\ln 3}$.
Question 5
6 marksHLGDC required
Advanced Integration — volume of revolution about the $y$-axis
The region $R$ is enclosed by the curve $y = \ln x$, the $x$-axis, the $y$-axis, and the horizontal line $y = 2$. The region is rotated $360°$ about the $y$-axis.
(a) Express $x$ in terms of $y$. [1]
(b) Write down the definite integral for the volume $V$ using the disc method. Give as pi*int(f(y), a, b). [2]
(c) Evaluate the exact volume. Give in the form $\dfrac{\pi}{2}(e^k - 1)$ and state $k$. [3]