Given a random variable $X$  normally distributed as $\operatorname{N}(m,\sigma^2)$ find probabilities $P(X \gt a),\; a \gt m;\;\;P(X \lt b),\;b \lt m$.

Explain why one variable is a factor but the other is not. Factorise the expression, whose factor is alphanumeric. Part of HELM Book 1.3

Show one of several blocks of text depending on the value of a question variable.

As well as a simple check for the value of a variable, the condition to display a block of text can be a complex expression in any of the question variables - in this example, depending on the discriminant of the generated quadratic.

No description given

Given an expression in one or two variables, with two or three terms, collect like terms, if possible. Part of HELM Book 1.3

Compare ax-bx, and ax(bx) and simplify, where a and b are +ve or -ve integers, and x is a randomised variable. Part of HELM Book 1.3

Write an expression (a^k1*a^k2)/a^k3 using a single positive index. Variable a is randomised and can be a number or a letter. k1,k2 and k3 are randomised positive numbers.

Part of HELM Book 1.2

Given an expression (either a^-k or 1/a^-k) with a negative index, rewrite it with a positive index.

The variable a and the index k are randomised.

Part of HELM Book 1.2

An order of operation question using +,-,* with signed integers, with up to 4 variables.

The questions are the exercises from Q3 of HELM Book 1.1.5

This exercise will help you rearrange some complex equations.

Simplify (a^k1*a^k2)/(a^k3*a^k4) where a is a randomised variable and k1,k2,k3 and k4 are randomised fractions (k2 and/or k4 may be 0). They may be written in index form or in surd form, or even a combination of the two.

Part of HELM Book 1.2

Write an expression (a^k1*a^k2)/a^k3 using a single positive index. Variable a is randomised and can be a number or a letter. k1,k2 and k3 are randomised and can be positive or negative numbers.

Part of HELM Book 1.2

Given an expression (either a^-k or 1/a^-k) with a negative index, rewrite it with a positive index.

The variable a and the index k are randomised.

Part of HELM Book 1.2

Simplify n1.v^k1.(n2.v^k2), where n1, n2 are positive integers, v is a random letter variable, and k1 and k2 are nonzero integers.

The answer should be expressed as n.v^k

Part of HELM Book 1.2

Remove the brackets from (na)^k, or from n(a)^kwhere n is a number and a is a variable.

Part of HELM Book 1.2

Use the index laws to simplify 3 simple expressions;

n^a*n^b, n^a/n^b, (n^a)^b, where n is a randomised variable or number, and a and b are randomised nonzero integers.

Part of HELM Book 1.2

Expand (x+a)(x+b)(x+c), where x is a randomised variable, and a,b,c are randomised integers.

Note that the pattern restriction in the marking checks that there are no brackets and that the expression is simplified to at most a single x^3, x^2, x and constant term; but it will let you get away with an additional -x^2 and/or -x term. (e.g., you could write 3x as 4x -x and the marking would accept this. This was to stop the pattern matching getting too complicated.

Part of HELM Book 1.3

Recovering original function given some information such as derivative and value at some point.

Crear una tabla de verdad para una expresión lógica de la forma :

\[[(a \ {op1}\ b) \ {op2}\ (c \ {op3}\ d)] \ {op4} [e\ {op5}\ f]]\]

donde cada una de $a, \; b, \; c, \; d, \; e, \; f $ puede ser una de las variables booleanas \[ p, \; q, \; \neg p, \; \neg q\]  y cada uno de los operados $\ {op} $  puede ser uno de los operadores $ \lor, \; \land, \; \to $.

Crear una tabla de verdad para una expresión lógica de la forma:

$$(a \ {op1}\,\  b) \ {op2}\,\ (c \ {op3} \,\ d)$$

donde $a, \;b,\;c,\;d$ pueden variables booleanas $p,\;q,\;\neg p,\;\neg q$  y cada operador  $\operatorname{op1},\;\operatorname{op2},\;\operatorname{op3}$  es uno de los conectivos $\lor,\;\land,\;\to$.

Por ejemplo: $(p \lor \neg q) \land(q \to \neg p)$.

The student must write R code to assign the given value to the variable x.

Given an unknown list, the student must write Python code to create a copy of it.

There's an alternative to catch the case where the student's variable is just a reference to the original list.

This is the simplest demonstration of the "code" part type I could think of: assign x = 1.

An alternative answer gives a hint if the studen'ts code doesn't define x at all.

Finding the modulus and argument (in radians) of four complex numbers; the arguments between $-\pi$ and $\pi$ and careful with quadrants!

Find modulus and argument of two complex numbers. Then use De Moivre's Theorem to find positive powers of the complex numbers.

The answer to this question is a differential equation involving $y''$, $y'$ and $y$.

A variable value generator for $y$ ensures that the right values are tested to check that the student's answer is equivalent to the expected equation.

This question includes a JavaScript preamble which defines 'hbar' as a special variable name to be rendered in LaTeX as \hbar.

Solving a differential equation of the form $\frac{dy}{dx}=\frac{ax^n}{y}$ using separation of variables.

Solving a differential equation of the form $\frac{dy}{dx}=axy^2$ using separation of variables.

Solving a differential equation of the form $\frac{dy}{dx}=axy$ using separation of variables.