Kumamoto Entrance Science study materials
Kumamoto Entrance Science study resources

Kumamoto Entrance Science key terms

Kumamoto Entrance Science · Get comfortable with the vocabulary.

極限 (limit)

The value a function or sequence approaches as its input or index gets arbitrarily close to a target. In Japanese Mathematics III it underpins differentiation and integration, and you must often distinguish one-sided limits.

Related: 微分係数 (derivative at a point), 連続性 (continuity)
微分係数 (derivative at a point)

The instantaneous rate of change of a function at one point, defined as the limit of the difference quotient. Geometrically it is the slope of the tangent line at that point.

Related: 極限 (limit), 接線 (tangent line)
接線 (tangent line)

A straight line touching a curve at a point with the same slope as the curve there. Its equation uses the derivative evaluated at that point, often written y minus f(a) equals f prime of a times x minus a.

Related: 微分係数 (derivative at a point), 法線 (normal line)
定積分 (definite integral)

The limit of a sum of rectangular areas over an interval, giving signed area under a curve. It is computed using an antiderivative evaluated at the upper and lower bounds and subtracted.

Related: 原始関数 (antiderivative), 区分求積法 (summation by subdivision)
原始関数 (antiderivative)

A function whose derivative equals a given function. Any two antiderivatives of the same function differ only by a constant, which is why indefinite integrals carry an arbitrary constant.

Related: 定積分 (definite integral), 置換積分 (integration by substitution)
置換積分 (integration by substitution)

A technique that rewrites an integral in a new variable to simplify it. You must also transform the differential and, for definite integrals, change the limits of integration accordingly.

Related: 原始関数 (antiderivative), 部分積分 (integration by parts)
部分積分 (integration by parts)

A rule derived from the product rule that integrates a product of two functions by trading one factor's derivative for the other's integral. Choosing which factor to differentiate is the key skill.

Related: 置換積分 (integration by substitution), 定積分 (definite integral)
漸化式 (recurrence relation)

An equation expressing a sequence term in terms of earlier terms. Solving it means finding an explicit formula, often by guessing a shifted geometric form or using characteristic equations.

Related: 数学的帰納法 (mathematical induction), 等差・等比数列 (arithmetic and geometric sequences)
数学的帰納法 (mathematical induction)

A proof method for statements about all natural numbers: verify the base case, assume the statement for n equals k, then prove it for k plus one. Both steps are required for full credit.

Related: 漸化式 (recurrence relation), 背理法 (proof by contradiction)
場合の数 (counting outcomes)

The number of ways an event can occur, computed with permutations when order matters and combinations when it does not. Distinguishing ordered from unordered selection is the central skill.

Related: 確率 (probability), 順列・組合せ (permutations and combinations)
確率 (probability)

A number from zero to one measuring how likely an event is, often as favorable outcomes divided by total equally likely outcomes. Conditional probability and independence are frequently tested extensions.

Related: 場合の数 (counting outcomes), 期待値 (expected value)
ベクトル (vector)

A quantity with both magnitude and direction, represented by components or arrows. In Mathematics B you use dot products, position vectors, and vector equations of lines and planes.

Related: 内積 (dot product), 位置ベクトル (position vector)
内積 (dot product)

A scalar formed from two vectors, equal to the product of their magnitudes and the cosine of the angle between them. It is zero exactly when the vectors are perpendicular.

Related: ベクトル (vector), 法線ベクトル (normal vector)
複素数平面 (complex plane)

A coordinate plane where a complex number a plus bi is plotted at point (a, b). Multiplication by i rotates a point ninety degrees, and modulus and argument describe polar position.

Related: ド・モアブルの定理 (de Moivre's theorem), 極形式 (polar form)
ド・モアブルの定理 (de Moivre's theorem)

The rule that raising a complex number in polar form to a power multiplies its argument by that power and raises its modulus to that power. It simplifies powers and roots of complex numbers.

Related: 複素数平面 (complex plane), 極形式 (polar form)
運動方程式 (equation of motion)

Newton's second law written as mass times acceleration equals net force. Solving mechanics problems usually begins by drawing a free-body diagram and resolving forces along chosen axes.

Related: 力のつり合い (force equilibrium), 摩擦力 (friction)
力学的エネルギー保存則 (conservation of mechanical energy)

When only conservative forces do work, the sum of kinetic and potential energy stays constant. It converts otherwise difficult force-and-time problems into simple energy bookkeeping.

Related: 仕事 (work), 運動量保存則 (conservation of momentum)
運動量保存則 (conservation of momentum)

The total momentum of a system stays constant when no external force acts on it. It is essential for collisions and explosions, where internal forces cancel in pairs.

Related: 力積 (impulse), 反発係数 (coefficient of restitution)
反発係数 (coefficient of restitution)

The ratio of relative separation speed to relative approach speed for two colliding bodies. A value of one means perfectly elastic, zero means perfectly inelastic, and between means partially elastic.

Related: 運動量保存則 (conservation of momentum), 力積 (impulse)
単振動 (simple harmonic motion)

Oscillation where restoring force is proportional to displacement and directed toward equilibrium. Displacement follows a sine curve, and period depends on mass and the spring or restoring constant.

Related: 周期と振動数 (period and frequency), ばね定数 (spring constant)
波の重ね合わせ (superposition of waves)

When two waves meet at a point, the resulting displacement is the sum of their individual displacements. This explains interference, standing waves, and beats between close frequencies.

Related: 定常波 (standing wave), 干渉 (interference)
ドップラー効果 (Doppler effect)

The change in observed frequency when a wave source and observer move relative to each other. Approaching raises observed frequency, and receding lowers it, according to relative speed.

Related: 波の重ね合わせ (superposition of waves), 屈折 (refraction)
全反射 (total internal reflection)

When light travels from a denser to a less dense medium beyond the critical angle, no light refracts out and all reflects internally. The critical angle satisfies sine of it equals the index ratio.

Related: 屈折 (refraction), 波の重ね合わせ (superposition of waves)
電場 (electric field)

The force per unit positive charge at a point in space, a vector quantity. Field lines point away from positive charge and toward negative charge, and the field is uniform between parallel plates.

Related: 電位 (electric potential), クーロンの法則 (Coulomb's law)
電位 (electric potential)

The electric potential energy per unit positive charge at a point, measured relative to a chosen zero. Charge moves spontaneously from higher to lower potential, and potential difference drives current.

Related: 電場 (electric field), キルヒホッフの法則 (Kirchhoff's laws)
キルヒホッフの法則 (Kirchhoff's laws)

Two rules for circuits: current into a junction equals current out, and the sum of potential changes around any closed loop is zero. They solve multi-loop circuits with several batteries.

Related: 電位 (electric potential), 電磁誘導 (electromagnetic induction)
電磁誘導 (electromagnetic induction)

A changing magnetic flux through a circuit induces an electromotive force. Lenz's law says the induced current opposes the change that produced it, which determines the current's direction.

Related: キルヒホッフの法則 (Kirchhoff's laws), 電場 (electric field)
モル (mole)

The amount of substance containing Avogadro's number of particles, about 6.02 times ten to the twenty-third. It links mass, particle count, and gas volume in stoichiometric calculations.

Related: モル濃度 (molarity), 化学反応式 (chemical equation)
モル濃度 (molarity)

The number of moles of solute per liter of solution, written mol/L. It is used in titration calculations and dilution problems, where moles of solute stay constant on dilution.

Related: モル (mole), 中和滴定 (acid-base titration)
中和滴定 (acid-base titration)

A procedure adding a solution of known concentration to a measured volume of unknown until neutralization. At the equivalence point, moles of hydrogen ion equal moles of hydroxide ion.

Related: モル濃度 (molarity), pH (水素イオン指数)
pH (水素イオン指数)

A logarithmic scale of hydrogen ion concentration, defined as the negative base-ten logarithm of that concentration. A change of one unit means a tenfold change in acidity.

Related: 中和滴定 (acid-base titration), 緩衝液 (buffer solution)
酸化還元反応 (oxidation-reduction reaction)

A reaction in which electrons transfer between species: one is oxidized, losing electrons, and another is reduced, gaining them. Oxidation numbers track the electron shift.

Related: 酸化数 (oxidation number), 電気分解 (electrolysis)
電気分解 (electrolysis)

Using an external voltage to drive a nonspontaneous redox reaction in an electrolyte. The amount of substance deposited or released is proportional to the charge passed, per Faraday's law.

Related: 酸化還元反応 (oxidation-reduction reaction), ファラデー定数 (Faraday constant)
化学平衡 (chemical equilibrium)

A reversible reaction's state where forward and reverse rates are equal, so concentrations stay constant though reactions continue. The equilibrium constant expresses the ratio of product to reactant concentrations.

Related: ル・シャトリエの原理 (Le Chatelier's principle), 平衡定数 (equilibrium constant)
ル・シャトリエの原理 (Le Chatelier's principle)

When a system at equilibrium is disturbed, it shifts in the direction that counteracts the disturbance. Changing concentration, pressure, or temperature shifts equilibrium predictably.

Related: 化学平衡 (chemical equilibrium), 平衡定数 (equilibrium constant)
有機化合物の官能基 (functional group)

An atom or group of atoms that gives an organic molecule its characteristic reactions, such as hydroxyl, carboxyl, aldehyde, or amino groups. Identifying it predicts properties and reaction products.

Related: 異性体 (isomer), エステル化 (esterification)
異性体 (isomer)

Molecules with the same molecular formula but different arrangements of atoms, giving different properties. Structural, geometric, and optical isomerism are the main categories tested.

Related: 有機化合物の官能基 (functional group), 光学異性体 (optical isomer)
細胞小器官 (organelle)

A membrane-bound or structurally distinct part of a cell with a specific function, such as mitochondrion, chloroplast, or ribosome. Comparing which organelles appear in plant and animal cells is a common question.

Related: 原核細胞と真核細胞 (prokaryotic and eukaryotic cells), 細胞膜 (cell membrane)
原核細胞と真核細胞 (prokaryotic and eukaryotic cells)

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both. Bacteria are prokaryotic; plants, animals, fungi, and protists are eukaryotic.

Related: 細胞小器官 (organelle), 細胞膜 (cell membrane)
光合成 (photosynthesis)

The process by which plants, algae, and some bacteria use light energy to convert carbon dioxide and water into organic matter and oxygen. It occurs in chloroplasts, in light and dark reactions.

Related: 呼吸 (cellular respiration), 気孔と蒸散 (stomata and transpiration)
呼吸 (cellular respiration)

The breakdown of organic molecules to release energy stored as ATP, using oxygen in aerobic forms. It occurs partly in the cytoplasm and partly in mitochondria, producing carbon dioxide and water.

Related: 光合成 (photosynthesis), 細胞小器官 (organelle)
遺伝の法則 (laws of inheritance)

Mendel's rules: traits are controlled by paired factors that separate during gamete formation and assort independently when on different chromosomes. These predict offspring ratios in crosses.

Related: 遺伝子型と表現型 (genotype and phenotype), 減数分裂 (meiosis)
減数分裂 (meiosis)

A cell division producing four haploid gametes from one diploid cell through two divisions. Crossing over and independent assortment during meiosis generate genetic variation.

Related: 遺伝の法則 (laws of inheritance), 遺伝子型と表現型 (genotype and phenotype)
ホルモンとフィードバック (hormones and feedback)

Hormones are chemical messengers secreted into blood that act on target organs. Negative feedback keeps levels stable, as when rising thyroid hormone suppresses further stimulation from the pituitary.

Related: 自律神経系 (autonomic nervous system), 恒常性 (homeostasis)
プレートテクトニクス (plate tectonics)

The theory that Earth's rigid outer shell is divided into plates that move over the mantle. Their interactions at boundaries cause earthquakes, volcanoes, and mountain building.

Related: 地震のP波とS波 (P and S waves), 火山とマグマ (volcanoes and magma)
地震のP波とS波 (P and S waves)

P waves are longitudinal and travel fastest; S waves are transverse and slower, and cannot pass through liquids. The time gap between their arrivals locates an earthquake's epicenter.

Related: プレートテクトニクス (plate tectonics), マグニチュードと震度 (magnitude and seismic intensity)
マグニチュードと震度 (magnitude and seismic intensity)

Magnitude measures the energy released at an earthquake's source on a logarithmic scale. Seismic intensity measures shaking strength at a specific location, so one quake has one magnitude but many intensities.

Related: 地震のP波とS波 (P and S waves), プレートテクトニクス (plate tectonics)
地球の大気の鉛直構造 (vertical structure of the atmosphere)

The atmosphere is layered by temperature trend: troposphere cools with height, stratosphere warms because ozone absorbs ultraviolet, mesosphere cools, and thermosphere warms again. Weather occurs mainly in the troposphere.

Related: 気圧と風 (pressure and wind), 地球の熱収支 (Earth's heat budget)
地球の熱収支 (Earth's heat budget)

The balance between incoming solar radiation absorbed and outgoing infrared radiation emitted by Earth. Greenhouse gases slow the outgoing radiation, raising surface temperature.

Related: 地球の大気の鉛直構造 (vertical structure of the atmosphere), 気圧と風 (pressure and wind)
主語と動詞の一致 (subject-verb agreement)

The verb must match its subject in number and person, even when phrases separate them. Inverted sentences and collective nouns are frequent traps in grammar questions.

Related: 関係代名詞 (relative pronoun), 分詞構文 (participial construction)
関係代名詞 (relative pronoun)

A word such as who, which, or that that introduces a clause modifying a noun. Choosing it depends on whether the antecedent is a person or thing and on the clause's grammatical role.

Related: 分詞構文 (participial construction), 仮定法 (subjunctive mood)
分詞構文 (participial construction)

A reduced clause using a present or past participle to express reason, time, condition, or result. The participle's subject normally matches the main clause's subject.

Related: 関係代名詞 (relative pronoun), 主語と動詞の一致 (subject-verb agreement)
仮定法 (subjunctive mood)

Verb forms expressing unreal or hypothetical situations, such as if I were you. Past forms refer to present unreality, and past perfect forms refer to unreal past situations.

Related: 関係代名詞 (relative pronoun), 倒置構文 (inversion)
パラグラフの主題文 (topic sentence)

The sentence stating a paragraph's main idea, usually placed first. In reading and composition tasks, locating it quickly reveals the paragraph's purpose and the writer's argument structure.

Related: 指示語の照応 (pronoun reference), 接続詞の機能 (function of conjunctions)
漢字の読み書き (kanji reading and writing)

Correctly reading and writing the kanji designated for upper secondary study, including on and kun readings and radical composition. Common traps involve similar-looking characters and readings that change with context.

Related: 同音異義語 (homophones), 四字熟語と慣用句 (four-character idioms and set phrases)
古文の助動詞 (classical Japanese auxiliary verbs)

Inflecting suffixes attached to classical Japanese words that add meaning such as past, negation, conjecture, or politeness. Each has a required connection form, and identifying it is essential for translation.

Related: 敬語の種類 (types of honorific language), 漢文の返り点 (kanbun reading marks)
敬語の種類 (types of honorific language)

Japanese polite language divides into respectful, humble, and polite forms. Choosing correctly depends on whether the action belongs to the speaker, the listener, or a third party being respected.

Related: 古文の助動詞 (classical Japanese auxiliary verbs), 同音異義語 (homophones)
評論の論理展開 (argument structure in expository essays)

The way a Japanese expository essay develops its claim through examples, contrasts, and qualifications. Identifying the author's conclusion and the relation between paragraphs is central to comprehension questions.

Related: 指示語の照応 (pronoun reference), 接続詞の機能 (function of conjunctions)