Skip to main content

Area under a curve

For a positive function, the integral between two bounds is the area caught between its graph and the horizontal axis. Picture it as a shaded region whose top edge is the curve and whose sides are two vertical lines.

In the picture

  1. The curve: the graph of the positive function whose height shapes the region.
  2. The shaded region: the area under the curve between the two bounds.
  3. The left vertical line: the lower bound of the interval.
  4. The right vertical line: the upper bound of the interval.

Examples

  • Distance travelled from a speed-time graph when speed changes.
  • Water collected from a rainfall rate that changes during the day.

Quiz: Area under a curve (Age 18)

  1. For a positive function, what does the integral between two bounds represent?

    • The greatest height reached by the function over that interval.
    • The slope of the curve at one of the bounds.
    • The area trapped between the curve and the horizontal axis over that interval.
  2. If the curve stays above the horizontal axis, what sign does the integral have?

    • It is negative.
    • It is positive.
    • It is exactly zero.
  3. What happens to the shaded area if either bound is changed?

    • The curve becomes the horizontal axis.
    • It stays exactly the same.
    • Its width and size change.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.

Get the app

Free app, optional subscription
App Store Google Play

Carry on in the app

At least one new illustrated lesson every weekday for your child’s year, with its quiz and a reminder at 6:15 pm.

Your child’s teacher does not use My Enhanced Teacher yet?

Tell them about it

Maths, Age 18