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    i am struggling with differentiation: rate of change.

    a funnel has a circular top of diameter 20cm and a height of 30cm. when the depth of liquid in funnel is 15cm, the liquid is dripping from the funnel at a rate of 0.2cm^3s^-1. at what rate is the depth of the liquid in the funnel decreasing at this instant?
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    (Original post by alosky)
    i am struggling with differentiation: rate of change.

    a funnel has a circular top of diameter 20cm and a height of 30cm. when the depth of liquid in funnel is 15cm, the liquid is dripping from the funnel at a rate of 0.2cm^3s^-1. at what rate is the depth of the liquid in the funnel decreasing at this instant?
    Funnel = cone = right cone = similar triangles
    you have dv/dt
    you want dh/dt
    can you make a chain? do you know/need the equation of a right cone?/can you use similar triangles to express h in terms of r (height and radius)?

    Chuck something together using similar triangles and see what happens.
 
 
 
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