Problems from The average change

Given the function f(x)=x2+x,

find the average change (AC) in the interval [0,10] and [0,2].

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Development:

Using the definition AC=yx=f(a+x)f(a)x Given the interval [0,10],

Δy=f(10)f(0)=(102+10)0=110

Δx=100=10

AC=ΔyΔx=11010=11

Given the interval [0,2]

Δy=f(2)f(0)=(22+2)0=6

Δx=20=2

AC=ΔyΔx=62=3

Solution:

Interval [0,10]: AC=11

Interval [0,2]: AC=3

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