Maths with Lemon

Areas and Volumes

"In my free time I do differential and integral calculus. "

Karl Marx

Areas of Integrals

What you have to know:

Areas

  • 1. Watch the video:

Volumes of integrals

What you have to know:

Key Points

  • 1. Watch the video:

Extra

Material and references:

  • Hodder Book HL(ISBN: 9781510462366) :
    10I

Key Points

  • You should know that the area bounded by a curve \( x = g(y) \), the \( y \)-axis and the lines \( y = c \) and \( y = d \) is given by \[ \int_c^d g(y)\,dy. \]

  • You should know how to find volumes of revolution. The volume formed when the part of the curve \( y = f(x) \), between \( x = a \) and \( x = b \), is rotated about the \( x \)-axis is \[ V = \int_a^b \pi y^2\,dx. \] The volume formed when the part of the curve \( x = f(y) \), between \( y = c \) and \( y = d \), is rotated about the \( y \)-axis is \[ V = \int_c^d \pi x^2\,dy. \]

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