Diagram Masterclass

Provenance: written 2026-09-29. Sources checked before writing: research/veridian/WMA13-verified-facts.md (the primary, provenance-checked source — its spec table §1, its per-topic evidence in §5 for spec 1.3, 1.4, 2.1, 3.1 and 3.3, and its audit-scope note that mark-scheme/examiner-report coverage spans 11 series of mark schemes and 8 full examiner reports); content/veridian/curriculum/wma13/modulus-and-graph-transformations.ts, exponentials-and-logarithmic-graphs.ts and reciprocal-and-inverse-trigonometric-functions.ts (the three lessons whose spec points involve a graph); content/veridian/curriculum/wma13/paper-anatomy.ts (the paper's general M/A/B marking guidance); and, inside this folder, signal-frequency-and-boundaries.md, signal-topic-brief-modulus-and-graph-transformations.md and codex-formula-and-method-bank.md, checked so this document adds something new rather than repeating what they already say. No new primary-source PDF was downloaded for this pass; every claim below traces to material already verified in WMA13-verified-facts.md or to the lesson/technique-hub files named above. Nothing here overrides or edits any of those documents.

#WMA13 Diagram/Graph Masterclass — applicability check

#Verdict: does not apply as a distinct, separately-markable skill

WMA13 (Maths Pure 3) mentions sketching in four spec points — 1.3 (the modulus function), 1.4 (combined transformations), 2.1 (reciprocal and inverse trig graphs) and 3.1/3.3 (exponential, log and log-linear graphs). But across every series this course has verified for this paper, a candidate's own drawn diagram is never the thing the mark scheme itemises. The marks attach to the algebra or the reasoning the sketch is used to produce — not to the sketch's own shape, asymptotes, or labelled points. That is a real, checkable difference from a subject where the diagram itself is the graded artefact (an economics supply/demand shift, a business decision tree, a mechanics force diagram), and it is why this masterclass is not being written as a full document.

#What the evidence actually shows, topic by topic

1.3–1.4, modulus and transformations. WMA13-verified-facts.md §5 and this folder's own signal-frequency-and-boundaries.md (row 1.3) list five verified series for the modulus sub-topic alone (Oct 2020, Jan 2022, Jun 2023, Jan 2024, Oct 2023) plus a sixth transformation-only series (Summer 2026 Q3). In every one, the real mark scheme's M/A/dM marks are for solving an equation or inequality (e.g. Jan 2022 Q7(b): M1 for one case, A1 for both critical values, dM1 for selecting the outside region, A1 for the final answer) or for correctly transforming a named point (Summer 2026 Q3(c)). The one case that is a graph argument rather than pure algebra — Jun 2023 Q6(d) — is a reflective-symmetry reasoning mark, not a re-sketch: this folder's own signal-topic-brief-modulus-and-graph-transformations.md already says so directly ("a reasoning mark, not a computation... not just a re-sketch"). No series in the audit shows a mark scheme awarding independent marks for the shape of a candidate's own drawn curve, its vertex, or its intercepts, in the way a "B1 for shape, B1 for each intercept" diagram question would.

2.1, reciprocal and inverse trig graphs. The lesson's own asymptote/range/period picture is a teaching diagram, built to explain why sec's asymptotes come from cos θ = 0 while cosec's and cot's come from sin θ = 0. No verified real WMA13 question in the audited series asks a candidate to produce that sketch for marks — the real, cited exam item for this spec point (Jan 2022 Q2) tests the reciprocal identity itself as a first algebraic step inside a larger trig equation, not a drawn graph.

3.1 and 3.3, exponential/log and log-linear graphs. The two verified real questions for parameter estimation from a log-linear graph (Jun 2023 Q2, Jun 2026 Q5) both give the candidate an already-plotted graph on the question paper, with its intercept and gradient shown. The marks are for reading those two numbers off the given line and converting them back (un-logging a gradient to get $b$, an intercept to get $a$) — never for the candidate drawing the graph themselves. exponentials-and-logarithmic-graphs.ts's own diagram blocks teach the $e^x$/$\ln x$ mirror-image sketch and the axis-reading mechanics; nothing in the verified facts shows a real exam question crediting a student's own exponential or log sketch as a distinct markable item.

#Why this is a real conclusion, not an assumption

The comparison the brief for this task asks for — economics supply/demand diagrams, business decision-tree diagrams, mechanics force diagrams and velocity-time graphs, statistics box plots — all share one property: the diagram itself is submitted as the answer, and the mark scheme decomposes it into separate creditable features (a shifted curve, a labelled equilibrium, a correctly branched tree). Pearson's own general marking guidance for this paper (quoted in paper-anatomy.ts, sourced from the January 2023 mark scheme and cross-checked against October 2023 and June 2022) does allow a B mark to be earned by "a graph" with no method shown — so the category exists in principle. What the verified evidence across 11 series of mark schemes shows is that this paper never actually exercises that category on a candidate-drawn sketch: every real graph-adjacent mark found is either algebra downstream of a mental sketch, a stated symmetry argument, or a reading taken from a graph the exam board already drew. Sketching on WMA13 is scratch work that earns marks indirectly, through the answer it produces, not a scored deliverable in its own right.

#What already covers the related content (not duplicated here)

• signal-topic-brief-modulus-and-graph-transformations.md — the graph-reading-vs-re-sketch distinction for 1.3/1.4.
• codex-formula-and-method-bank.md §1.3 — the two transformation results that must be reasoned from a sketch each time rather than memorised.
• modulus-and-graph-transformations.ts — the lesson's own diagram blocks teaching the |f(x)| / f(|x|) sketching mechanics.
• exponentials-and-logarithmic-graphs.ts — the lesson's own diagram blocks teaching the $e^x$/$\ln x$ mirror-image graph and log-linear axis reading.
• reciprocal-and-inverse-trigonometric-functions.ts — the lesson's own asymptote/range/period diagram.

#Conclusion

A full "Diagram/Graph Masterclass" for WMA13 would have to invent a mark-by-mark diagram rubric (shape, asymptote, intercept marks) that no verified series in this course's own research supports, or duplicate sketching mechanics the lessons above already teach. Both fail this course's standing sourcing discipline. This short document exists so that determination is written down once, with its evidence, rather than re-asked — and re-guessed — by a future pass.