# Math Help - these two questions are confusing for me i dont know where to get started.

1. ## these two questions are confusing for me i dont know where to get started.

1.if n inscribed rectangles were used, what would the expression be, in sigma () notation, that approximates the exact area? How is the value of this approximation related to the exact area of n approaches infinity?

2. Integrate the following:

a. (4 cos5x)dx

almost done this course!

2. ## Re: these two questions are confusing for me i dont know where to get started.

Originally Posted by alisunderani
1.if n inscribed rectangles were used, what would the expression be, in sigma () notation, that approximates the exact area? How is the value of this approximation related to the exact area of n approaches infinity?
This question seems to be taken out of context. Inscribed into what? It would help to post the complete question, including the information leading to it.

Originally Posted by alisunderani
2. Integrate the following:

a. (4 cos5x)dx
Have you tried differentiating sin(5x)?