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Mathematics

Divisibility and Group Structure Modulo 20

Further Maths question (see attached image). 2(i) Using a suitable algorithm and without performing any division, determine whether 13 306 617 is divisible by 9. 2(ii) The group G = {1, 3, 7, 9, 11, 13, 17, 19} has multiplication modulo 20 as its operation. (a) Complete the Cayley table for G. (b) State the inverse of the element 7. (c) Determine the order of the element 13. (d) Write down a subgroup of G of order 4.

Mathematics

Continuous Uniform Distributions

A-Level statistics question (see attached image). The graph of the probability density function f(x) of the continuous uniform random variable X is shown. The PDF is constant (height 0.2) from x = -3 to x = 2, and zero elsewhere. (a) Write down P(X = 1). (b) Find E(X). (c) Find Var(X). (d) Sketch the cumulative distribution function of X for -3 <= x <= 2, labelling points where it touches or crosses the axes. (e) Find P(X^2 > 1.96).

Mathematics

Complex Numbers and Rotations

A-Level question (see attached image). Let z = sqrt(3) - 3i. (a) Write z in the form r(cos theta + i sin theta) where -pi < theta <= pi. (b) Show and label on a single Argand diagram the point P representing z and the point Q representing iz. (c) Describe the geometrical transformation that maps P onto Q.

Mathematics

The Uncountability of the Continuum

Prove that the set of real numbers in the interval [0,1] is uncountable, using Cantor's diagonal argument.

Mathematics

Unmasking Hidden Quadratics

(a) Solve the quadratic equation x^2 - 5x + 6 = 0. (b) Hence solve the equation x^4 - 5x^2 + 6 = 0, giving all real roots.

Machine Learning

Demystifying Gradient Descent in Neural Networks

Explain how gradient descent trains a simple neural network. Describe the loss, the gradient and the weight update rule.

Machine Learning

Deriving the Output Weight Update in Backpropagation

Derive the backpropagation weight update rule for the output layer of a 2-layer neural network with sigmoid activation and a mean squared error loss.

Computer Science

Mastering Binary Search

Explain how the binary search algorithm works on a sorted array, and state its time complexity in big-O notation.

Computer Science

Solving the Divide and Conquer Recurrence

Solve the recurrence relation T(n) = 2 T(n/2) + n for n a power of 2, with T(1) = 1. Find a closed form for T(n) and state the asymptotic complexity.

Mathematics

Unlocking the Integral of ln(x)

Use integration by parts to find the integral of ln(x) with respect to x, and hence evaluate the definite integral from 1 to e.

Engineering

Unveiling Thevenin Equivalence

Find the Thevenin equivalent voltage and resistance of a circuit consisting of a 12 V source in series with a 4 ohm resistor, which is in parallel with a 6 ohm resistor. Explain the method.

Physics

Quantum Particles in a Box

Derive the quantised energy levels for a particle of mass m in a one-dimensional infinite potential well of width L, by solving the time-independent Schrodinger equation with appropriate boundary conditions.

Engineering

The Geometry of Bending: A Central Point Load

A simply supported beam of length 4 m carries a point load of 10 kN at its centre. Determine the maximum bending moment and draw the bending moment diagram.

Physics

The Geometry of Projectile Motion

A ball is thrown from ground level at 20 m/s at an angle of 30 degrees above the horizontal. Find the horizontal range of the ball. Take g = 9.8 m/s^2.

Physics

Understanding Motion: Speed and Distance

A car starts from rest and accelerates at 2 m/s^2 for 5 seconds. Calculate its final speed and the distance it travels in that time.

Mathematics

Unlocking Integrals: The Art of Integration by Parts

Find the integral of x e^(2x) with respect to x, using integration by parts. Show full working.

Mathematics

Proving the Sum of Cubes by Induction

Prove by mathematical induction that 1^3 + 2^3 + ... + n^3 = [n(n+1)/2]^2 for all positive integers n.

Mathematics

Unlocking Eigenvalues: The Geometry of Linear Transformations

Find the eigenvalues and a corresponding eigenvector for each, of the matrix [[2,1],[1,2]].

Mathematics

Solving Linear Equations: The Balancing Act

Solve the equation 3x + 7 = 22 and explain each step.

Mathematics

Finding a Fraction of a Number

What is 3/4 of 24? Show me how to work it out with fractions.

Mathematics

Understanding the Area of a Circle

A circle has radius 7 cm. Calculate its area, leaving your answer in terms of pi.

Mathematics

Integrating Products with Parts

solve

Mathematics

Estimating and Calculating Areas Under Curves

solve

Mathematics

The Symmetry of the Cube

explain to me the connection between a rubix cube and group theory.

Mathematics

Understanding Backpropagation: The Geometry of Learning

explain to me backpropogation very in depth at uni level, clear visuals

Mathematics

The Intuition of Backpropagation

explain to me backpropogation

Mathematics

The Intuition Behind Backpropagation

explain to me how backpropogation works

Mathematics

The Intuition Behind the Chain Rule

Explain the chain rule with a worked example and a diagram of the composite function.

Mathematics

Visualizing Gradient Descent

EXPLAIN HOW GRADIENT DESCENT WORKS

Mathematics

The Intuition of Integration by Parts

Explain integration by parts with a worked example, and include a diagram where it helps.

Mathematics

The Intuition Behind the Kalman Filter

explain to me how a kalman filter works

Mathematics

Why the derivative of sin(x) is cos(x)

Explain why the derivative of sin(x) is cos(x), intuitively.

Machine Learning

Gradient Descent in Plain Sight

Explain gradient descent and how it learns, with a visual analogy.

Mathematics

The Geometric Intuition of the Derivative of Sine

Explain why the derivative of sin(x) is cos(x), intuitively.