Mathématiques et sciences (mathématiques, physique, chimie, biologie)
What the papers test
Mathematics, physics, chemistry and biology papers test formal reasoning, modelling and data interpretation. In mathematics, the problème requires justified steps, not just answers. In physics and chemistry, expect calculations with units, graphs and experimental reasoning. In biology, expect data analysis, genetics, ecology and experimental design. Diagrams must be labelled; calculations must be set out.
Core rules
- State the formula before substituting; carry units through and give them in the answer.
- Respect domains and constraints (e.g. x>0 for ln x; denominator ≠ 0).
- Round only at the end; keep significant figures consistent with the data.
- In biology, identify the independent, dependent and controlled variables; distinguish correlation from causation.
Worked example
Find the tangent to f(x)=x ln x at x=e. Domain: x>0. f(e)=e·1=e. f′(x)=1·ln x + x·(1/x)=ln x+1, so f′(e)=2. Tangent: y−e=2(x−e), hence y=2x−e. Reasoning: differentiate with the product rule, evaluate at the point, then use point–slope form. A common error is using f′(e) as the y-intercept or forgetting the domain.
Traps
Dropping units or mixing them (g vs kg); premature rounding; ignoring the physical meaning of a negative root; writing a conclusion without linking it to the evidence; in chemistry, unbalanced equations; in biology, assuming a cause from a correlation.