[ Interactive Graph | Exponential Graph ] PR4: Scoring Logic

[SonicScrewdriver]

Summary:

This PR was created with the help of AI, albeit with heavy oversight and review. New pr because branch died.

This is part of a series of PRs implementing the exponential graph type for
the Interactive Graph widget:

PR1 – type definitions and schema
PR2 – state management
PR3 – rendering & accessibility
▶️ PR4 – scoring (this PR)
PR5 – editor support

Issue: LEMS-3711

• Added scoring logic for the exponential graph type

• Implements correctness scoring for exponential graphs by comparing the
  coefficients of the learner's curve against the rubric's correct answer,
  rather than comparing raw coordinates. This means any two curves that
  describe the same f(x) = a·eᵇˣ + c are scored as equivalent regardless
  of which specific points the learner placed.

Changes:

• score-interactive-graph.ts — Adds an "exponential" branch to
  scoreInteractiveGraph. Calls getExponentialCoefficients on both the
  user input and the rubric's correct answer, then compares the resulting
  {a, b, c} coefficients using approximateDeepEqual. Returns full
  points if they match, falls through to the existing incorrect result
  otherwise. Guards against null coefficients (invalid geometry).
• score-interactive-graph.test.ts — Tests covering: correct answer
  (same curve, different point positions), incorrect answer (different
  curve), and incomplete input (null coords or asymptote).

Test plan:

• pnpm test packages/perseus-score — all new scoring tests pass
• pnpm tsc — no new type errors
• pnpm lint — no lint errors
• No existing scoring tests regress

[claude]

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[github-actions]

🗄️ Schema Change: No Changes ✅

[github-actions]

🛠️ Item Splitting: No Changes ✅

[github-actions]

Size Change: +80 B (+0.02%)

Total Size: 493 kB

Filename	Size	Change
packages/perseus-score/dist/es/index.js	9.58 kB	+80 B (+0.84%)

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	20.5 kB
packages/keypad-context/dist/es/index.js	1 kB
packages/kmath/dist/es/index.js	6.21 kB
packages/math-input/dist/es/index.js	98.5 kB
packages/math-input/dist/es/strings.js	1.61 kB
packages/perseus-core/dist/es/index.item-splitting.js	11.9 kB
packages/perseus-core/dist/es/index.js	25 kB
packages/perseus-editor/dist/es/index.js	101 kB
packages/perseus-linter/dist/es/index.js	9.02 kB
packages/perseus-utils/dist/es/index.js	403 B
packages/perseus/dist/es/index.js	193 kB
packages/perseus/dist/es/strings.js	8.09 kB
packages/pure-markdown/dist/es/index.js	1.39 kB
packages/simple-markdown/dist/es/index.js	6.71 kB

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[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (a3dbb02) and published it to npm. You
can install it using the tag PR3394.

Example:

pnpm add @khanacademy/perseus@PR3394

If you are working in Khan Academy's frontend, you can run the below command.

./dev/tools/bump_perseus_version.ts -t PR3394

If you are working in Khan Academy's webapp, you can run the below command.

./dev/tools/bump_perseus_version.js -t PR3394