Topic Brief: Graph Transformations in Words

Provenance: compiled 2026-09-29. Source is research/veridian/WMA11-verified-facts.md — specifically §4.1's "Graph transformations" entry, the 2026-09-14 mark-scheme-bullet coverage audit of graph-transformations-in-words.ts (the anchor re-verification that re-fetched and cross-checked all three primary sources below with pdftotext -layout/-raw), §6, and §7 — cross-checked against content/veridian/curriculum/wma11/graph-transformations-in-words.ts and content/veridian/technique-hub/wma11/signal-frequency-and-boundaries.md. This document does not restate either of those in full; it adds three syntheses neither states explicitly: the mark-tariff pattern across the three mined anchors, which framing ("describe in words" vs "state coordinates") each anchor actually uses, and the cross-series link between two opposite-direction scale-factor errors. Not affiliated with or endorsed by Pearson Edexcel.

#SIGNAL Topic Master Brief — Graph Transformations Described in Words

#WMA11 (Pure Mathematics P1), spec 1.12

#1. Where this has actually been tested

Seen in 4 of 5 fully-read series (the five series with a complete, question-by-question examiner report: Jan 2019, Oct 2020, Oct 2021, Jan 2023, Jan 2025 — denominator per signal-frequency-and-boundaries.md §1). Not confirmed in Jan 2025.

Three of the four listed series (Jan 2019, Oct 2021, Jan 2023) have a fully mined, quotable real question behind them. Oct 2020 is counted as a sighting because the topic is named there, but nothing beyond that should be treated as known about it — no question wording, mark code, or trap has been checked against its primary source.

#2. The real mark-tariff pattern

Every mark on all three fully-mined anchors is a B mark. Not one M or A mark appears anywhere in this topic's verified real coverage:

• Jan 2023 Q7(b) — "fully describe this transformation," 2 marks, B1 B1.
• Oct 2021 Q4(a)(i) — state two coordinates and a domain endpoint, 3 marks, B1 B1 B1.
• Jan 2019 Q8(a)/(b)/(c) — state an asymptote, state a turning point, state a range of k, B1 / B1 / B1 B1.

This is a real, checkable pattern, not a guess: this topic is marked on whether a specific fact was stated correctly (a word, a coordinate, a value), never on a method line. There is no partial credit route through "show working" the way there is on, say, a discriminant question — either the required word or number appears, or it doesn't. Jan 2023's examiner report makes the practical cost of this explicit: candidates who got the geometry entirely right still lost the mark for writing "shifts" instead of "translation" — a B-mark question has no method-shown fallback to fall back on.

#3. The recurring context/angle

Two patterns hold across all three mined anchors, neither of which is stated outright in the existing lesson file or the frequency table:

The topic's own name is the minority framing. Despite "described in words" being the lesson title, only Jan 2023 Q7(b) actually asks for a worded description. Oct 2021 Q4(a)(i) and Jan 2019 Q8 both ask candidates to state exact new coordinates of a tracked feature (a minimum point, a domain endpoint, a turning point, an asymptote) — the wording skill is implicit in getting the numbers right, not separately marked. A student expecting every appearance of this topic to demand a sentence like "translation, 2 units..." would be prepared for 1 of the 3 mined question types.

A labelled sketch carries real weight even when a formula also exists. Jan 2019 Q8's curve $C$ is defined purely by Figure 4 (a labelled sketch: one maximum, two axis crossings, one asymptote) — there is no equation for $f$ anywhere in that question, so every part is answered by reading a transformed feature off the picture. Oct 2021 Q4(a)(i) does state $f(x)=\cos(2x°)$ algebraically, but the question is still built around a labelled sketch (Figure 2, minimum point $Q$ and endpoint $R$ marked) and answered by reading coordinates off it, not by substituting into the equation. Only Jan 2023 Q7(b) ($y=6/x$ to $y=6/(x-2)$) is worked from algebra with no sketch in the source at all. Reading a transformed feature off a picture is therefore at least as central to this topic as manipulating an equation — in two of the three mined anchors, not just one.

The same scale-factor error recurs in both directions. Oct 2021 Q4(a)(i)'s documented misconception used $a=2$ where the reciprocal $\tfrac12$ was needed (treating a stretch as if the scale factor weren't inverted). Jan 2019 Q8(b)'s documented misconception used $a=\tfrac14$ directly where the reciprocal $4$ was needed — the mirror image of the same slip. Between the two, "forgetting to invert the $f(ax)$ scale factor" is independently confirmed running both ways, not just once.

#4. If this topic appears — what to expect

• A "describe fully" or "state the coordinates of [feature]" instruction attached to a curve that is either a simple algebraic form (a reciprocal or trig function) or a sketch with no formula at all.
• Full marks resting on B marks alone: a specific noun ("translation," "stretch" — never "shift," "move," or "compression") or a specific number, with no method credit available if that exact statement is missing.
• If it's a stretch of the $f(ax)$ form: expect the scale-factor-not-inverted trap to be live in either direction (using $a$ instead of $\tfrac1a$, or vice versa).
• If it's a translation: expect the direction-sign trap on $f(x+a)$ (moves by $-a$, not $+a$) to be live, alongside the vocabulary trap even when the direction and distance are both correct.
• No verified grade-boundary or percentage-likelihood figure exists for this or any WMA11 topic in this course's sources — per this course's standing rule, none is given here; see signal-frequency-and-boundaries.md §2 for why.

#5. What this brief does not claim

Oct 2020 Q2 and Q5 remain unmined — this brief repeats the facts bank's own flag rather than guessing at their content. No claim is made about any series beyond the five fully-read ones (Oct 2022, Jan 2024, June-series papers) touching this topic; absence from this brief means "not checked," not "did not appear."