The marginal cost function for the manufacturing of headphones is given by C'(x)=20-x/200 where x is the number of headphones made. Use a right riemann sum with n=5 to estimate the cost of producing the first 5 headphones.

Answer 1

Since each rectangle has width=1, just add up the function values:
1(C(1)+C(2)+C(3)+C(4)+C(5))

Answer 2

But how do I get C to plug the values in? I take the antiderivative and the extra variable for the end is unknown. What point do I have to find that so I am able to plug values in?

Answer 3

My bad. The total cost is the area under the curve for C'. So the sums involve C'(x), not C(x).