Bac C Bénin common mistakes
Bac C Bénin · Understand the traps and how to avoid them.
In mathematics, starting to differentiate or integrate without first writing the domain of validity, then treating a result valid on ℝ as valid on the interval actually imposed by the exercise (e.g. dividing by a term that vanishes at a point).
Candidates memorise formulas as recipes and skip the preliminary analysis step, because in class the teacher often supplies the domain; under exam pressure they jump straight to computation.
What to do instead
Adopt a fixed written ritual: before any calculation, write 'domaine d'étude' and solve the conditions (denominator ≠ 0, argument of ln > 0, radicand ≥ 0). Train on ten short exercises where only the domain is asked for, so the step becomes automatic and earns its own marks.
In mathematics, producing a bare numerical answer to a probability or geometry problem without justifying the model (equiprobability, independence, choice of a coordinate system), so the reasoning marks are lost even when the number is right.
Students conflate 'finding the result' with 'demonstrating', and the Bac scale rewards structured reasoning; many have never practised writing justification sentences in their own words.
What to do instead
Keep a personal list of standard justification sentences ('les issues sont équiprobables car…', 'dans le repère orthonormé choisi…') and, in every practice exercise, underline each sentence that justifies rather than computes. Have a peer check only the justification chain, not the final number.
In physics, writing a formula with quantities in mixed units (grams with litres, centimetres with seconds) and reporting a numerical result without its unit or with the wrong unit.
The reflex of converting to SI units before substituting is not yet automatic, and calculators hide dimensional errors because the number looks plausible.
What to do instead
Impose a two-column layout: left column 'grandeur, valeur en unité SI', right column 'calcul littéral'. Do not substitute any number until the literal expression is written. Check the unit by dimensional analysis before writing the final line.
In physics and chemistry, drawing a circuit, force diagram, or titration setup that is not labelled (no arrows, no names of forces, no polarity), making the diagram unusable as support for the reasoning.
Diagrams are treated as decoration rather than as a reasoning tool; students copy textbook figures without learning the conventions.
What to do instead
Practise producing diagrams from a blank page using a checklist: axes, arrows, labels, scale, and direction of conventional current. In mock exams, grade the diagram separately and refuse to accept an unlabelled one.
In French, writing a dissertation or commentary without a problem statement, producing a plan that lists themes rather than arguing a thesis, so the development is descriptive and never answers a question.
The 'problématique' is the hardest intellectual step and is often replaced by a recycled plan learned by heart; students fear that formulating a question will commit them to an indefensible position.
What to do instead
For each subject, force yourself to write one interrogative sentence and one thesis sentence before any plan. Practise converting a topic into a question using templates ('Dans quelle mesure…', 'En quoi…'). Have the teacher validate only these two sentences before you draft.
In French, quoting texts in a commentary without analysing the stylistic device: the quote is dropped in and paraphrased ('l'auteur dit que…') instead of being named and interpreted.
Students lack an active repertoire of figures and procedures, and paraphrasing feels safer than naming a device incorrectly.
What to do instead
Build a personal table of ten figures and ten syntactic procedures with one example each, and drill the sentence pattern 'citation + nom du procédé + effet produit'. In every paragraph, require at least one such analysed quote rather than a merely illustrative one.
In English, answering comprehension questions by copying a full sentence from the text without locating it or reformulating, and writing essays with memorised paragraphs unrelated to the prompt.
Copying feels safe for grammar, and pre-learned essay blocks are a common shortcut when vocabulary is limited.
What to do instead
Practise the discipline 'line reference + short quotation + reformulation in your own words'. For writing, prepare flexible functional phrases (opinion, contrast, concession) rather than whole paragraphs, and always re-read the prompt to check each paragraph answers it.
In philosophy, treating the dissertation as a catalogue of authors' opinions ('Platon pense que…, Descartes pense que…') without constructing a concept or confronting the authors on the question asked.
Students have learned author summaries as content and mistake erudition for argumentation; they have rarely practised building a conceptual distinction themselves.
What to do instead
Work from the question to the concept: define the key term, identify the implicit alternative, then use authors only as instruments to advance one precise step. Draft plans in which every part is stated as an assertion answering the question, and delete any paragraph that could be moved to another subject without change.
In history-geography, narrating events in chronological order without answering the question type (explain, characterise, compare), and using maps or documents only as illustrations rather than as evidence to be interpreted.
Revision is organised as story-telling and dates, while the exam commands ('analyser', 'expliquer') require a different cognitive operation that is rarely made explicit.
What to do instead
Before writing, underline the command word and rewrite it as a question. For each topic, prepare three 'because' chains linking cause, fact, and consequence. For documents, always extract two explicit pieces of information and state what they prove about the question.
In EPS, treating the practical tests as pure physical performance and neglecting the written or oral component (training plan, rules, analysis of a match), or arriving without knowing the evaluation criteria for the chosen activity.
Candidates assume EPS marks come only from athletic ability, and the evaluation grid is rarely read carefully; preparation time is spent only on the sport itself.
What to do instead
Obtain the official evaluation grid for your chosen activity and map each criterion to a concrete action you can rehearse. Prepare a one-page written analysis template (strengths, weaknesses, training principles, tactical choices) and rehearse it aloud so the written or oral part becomes free marks.