Angola Military Technical Institute (ISTM) Exam key terms

A function of the form f(x) = ax² + bx + c with a ≠ 0. Its graph is a parabola whose vertex and roots can be found using the coefficients.

The expression Δ = b² − 4ac in a quadratic equation. Its sign tells how many real roots the equation has: two, one, or none.

The highest or lowest point of a parabola, located at x = −b/(2a) for f(x) = ax² + bx + c. It marks the maximum or minimum value of the function.

A sequence in which each term after the first is obtained by adding a fixed number called the common difference. The general term is aₙ = a₁ + (n − 1)d.

A sequence in which each term after the first is obtained by multiplying by a fixed number called the common ratio. The general term is aₙ = a₁ · rⁿ⁻¹.

In a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c². It is used to find unknown lengths.

Ratios relating the sides of a right triangle to its acute angles: sine (opposite/hypotenuse), cosine (adjacent/hypotenuse) and tangent (opposite/adjacent). They allow calculation of unknown sides and angles.

The exponent to which a base must be raised to produce a given number: log_b(x) = y means bʸ = x. Logarithms turn products into sums and solve exponential equations.

A function of the form f(x) = aˣ with a > 0 and a ≠ 1. It grows or decays at a rate proportional to its current value and is the inverse of the logarithm.

The net force on a body equals its mass times its acceleration: F = m·a. It links force, mass and acceleration and is the basis of classical mechanics problems.

The rate at which velocity changes with time, measured in metres per second squared (m/s²). It can be caused by a change in speed, direction, or both.

Motion in which acceleration is constant, so velocity changes at a steady rate. Its position follows s = s₀ + v₀t + ½at².

Motion of a body under gravity alone, with air resistance ignored. Near Earth's surface the acceleration is about 9,8 m/s² directed downward.

Work is the transfer of energy when a force moves an object: W = F·d·cosθ. Energy is the capacity to do work, measured in joules.

The rate at which work is done or energy is transferred, measured in watts (W). It equals work divided by time: P = W/t.

For a conductor at constant temperature, the current is proportional to the voltage: U = R·I. It relates voltage, current and resistance in electrical circuits.

A closed path through which electric current flows, containing a source, conductors and components such as resistors. Components may be connected in series or in parallel.

The force that holds atoms together in a compound, such as ionic, covalent or metallic bonding. The type of bond affects properties like melting point and conductivity.

A chart arranging chemical elements by increasing atomic number, grouped by similar properties. Columns are groups and rows are periods.

The number of protons in the nucleus of an atom, denoted Z. It uniquely identifies the element and equals the number of electrons in a neutral atom.

The amount of substance containing 6,02 × 10²³ particles (Avogadro's number). It links mass, number of particles and volume in chemical calculations.

The mass of one mole of a substance, expressed in grams per mole (g/mol). It is numerically equal to the relative atomic or molecular mass.

A reaction between an acid and a base that produces a salt and water. It is an example of a double displacement reaction and typically releases heat.

A scale from 0 to 14 measuring the acidity or alkalinity of a solution. Values below 7 are acidic, 7 is neutral and above 7 is basic.

The roles language plays in communication: referential, emotive, conative, phatic, metalinguistic and poetic. Each function emphasises a different element of the communication act.

Expressive devices that enrich meaning, such as metaphor, comparison, personification and hyperbole. They are common in literary and persuasive texts.

A text whose purpose is to persuade the reader of a viewpoint, using a thesis, arguments and a conclusion. It relies on evidence and logical reasoning.

Words or phrases that link ideas between sentences and paragraphs, showing cause, contrast, addition or conclusion. They improve cohesion and coherence in writing.

A verb that needs a direct or indirect object to complete its meaning, such as 'comprar' or 'gostar de'. It contrasts with intransitive verbs, which stand alone.

The agreement between a verb and its subject in number and person. The verb must match the subject, as in 'os alunos estudam'.

An English verb tense formed with 'have/has + past participle'. It links a past action to the present, as in 'She has finished her work'.

An English tense describing completed actions in the past, often with a specific time. Regular verbs add -ed; irregular verbs change form, as in 'went'.

Sentences expressing a condition and its result, usually with 'if'. The first conditional uses present + will; the second uses past + would.

Auxiliary verbs such as can, must, should and may that express ability, obligation, permission or possibility. They are followed by the base form of the verb.

A construction where the object of an action becomes the subject, formed with 'be + past participle', as in 'The report was written'. It is used when the doer is unknown or unimportant.

The armed struggle waged by Angolan movements from 1961 against Portuguese colonial rule. It led to independence on 11 November 1975.

The January 1975 agreement between Portugal and the three Angolan liberation movements recognising Angola's independence. It established a transitional government that soon collapsed.

Angola became independent from Portugal on 11 November 1975, proclaimed by the MPLA in Luanda. The date is now celebrated as the national day.

Angola's relief rises from a narrow coastal plain to an interior plateau, the planalto, which covers most of the country. The highest point is Mount Moco.

Angola has a tropical climate, with a dry, cooler season (cacimbo) from May to September and a rainy season from October to April. Rainfall decreases from north to south.

A form of deductive reasoning with two premises leading to a conclusion, such as 'All men are mortal; Socrates is a man; therefore Socrates is mortal'.

A statement that can be judged either true or false, but not both. Logical operators such as 'and', 'or' and 'not' combine propositions.

A series of numbers, shapes or symbols that follow a hidden rule. The task is to identify the rule and predict the next element.

A collection of distinct objects, called elements, considered as a whole. Sets are described by listing elements or by a rule and are studied with union and intersection.

The Community of Portuguese Language Countries, founded in 1996, which brings together Portuguese-speaking nations. Angola is a founding member.

The Southern African Development Community, a regional organisation promoting economic integration and security among southern African states. Angola is a member.

A continental organisation of African states, created in 2002 to replace the OAU. It promotes unity, peace and development across the continent.