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Find the area between y=t and y=x for 0≤x≤t.

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2027 JM02 考試大綱 · 6. Basic calculus: integrals and area · PDF 2 / printed page 2

Revisit first: Derivative operations

TOPIC 01

Integration, area and school extensions

Find antiderivatives, evaluate definite integrals and distinguish signed accumulation from geometric area.

What you will be able to explain

  • Find antiderivatives, evaluate definite integrals and distinguish signed accumulation from geometric area.
  • Justify the method and check the conditions in a new situation.

Try it. Leave your reasoning visible.

Use one hint at a time. A correction explains what changed, not just the final answer.

01 / Standard#Your turn

Find the area between y=t and y=x for 0≤x≤t.

t=10t=10
  • An indefinite integral includes an arbitrary constant; split at sign changes when calculating area. Revolution volumes are a school extension (T06 PDF6–10).
Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1
Write the defining equation, retain exclusions, and then solve or compare.
Hint 2
Use this intermediate relation.
A=∫0t(t−x)dxA=\int_0^t(t-x)dx
Worked solution
  1. Write the defining equation, retain exclusions, and then solve or compare.

  2. Apply the stated relation and retain its conditions.

    A=[10x−x2/2]010=100/2A=[10x-x^2/2]_0^{10}=100/2
  3. Top minus bottom is nonnegative throughout this interval.

The requested value is 50.

Checks and common pitfalls: Top minus bottom is nonnegative throughout this interval.

Think first. Reveal a hint when the class is ready.

Focus on one question

Teacher preparation and assessment

Question sequence

  • Find antiderivatives, evaluate definite integrals and distinguish signed accumulation from geometric area.
  • Which condition is essential in integration, area and school extensions?
  • Can the signed integral be zero while the total area is positive?

Board plan

  • Model or definition: Find antiderivatives, evaluate definite integrals and distinguish signed accumulation from geometric area.
    ∫abf(x)dx=F(b)−F(a)\int_a^bf(x)dx=F(b)-F(a)
  • Conditions: An indefinite integral includes an arbitrary constant; split at sign changes when calculating area. Revolution volumes are a school extension (T06 PDF6–10).

Anticipated thinking

  • A negative definite integral is not a negative geometric area.

Assessment checklist

  • 1 mark: choose the correct representation and conditions.
  • 1 mark: establish the intermediate relation.
  • 1 mark: complete a connected calculation or proof.
  • 1 mark: interpret and check the conclusion.

No sign-in. Work stays in this browser. Export before clearing browser data. Written reasoning is assessed with a checklist.

Curriculum and source notes ↗