Identify each expression and value that represents the area under the curve y= x^2+4 on the interval [-3, 2].

The area is given exactly by the definite integral,

We can write this as a Riemann sum, i.e. the infinite sum of rectangular areas:

• Split up the integration interval into n equally-spaced subintervals, each with length (2 - (-3))/n = 5/n - - this will be the width of each rectangle. The intervals would then be

[-3, -3 + 5/n], [-3 + 5/n, -3 + 10/n], …, [-3 + 5(n - 1)/n, 2]

• Over each subinterval, take the function value at some point x * to be the height.

Then the area is given by

Now, if we take x * to be the left endpoint of each subinterval, we have

x * = -3 + 5(k - 1)/n   →   f (x *) = (-3 + 5(k - 1)/n)² + 4

If we instead take x * to be the right endpoint, then

x * = -3 + 5k/n   →   f (x *) = (-3 + 5k/n)² + 4

So as a Riemann sum, the area is represented by

and if you expand the summand, this is the same as

So from the given choices, the correct ones are

• row 1, column 1

• row 2, column 2

• row 4, column 2

step- i d k and i d c : )

you: : 0

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