$4.7 × 915 = 4300.5
$4300.5 + 79.15 = 4379.65
15% of 4379.65 = 656.9475
4379.65 + 656.9745 = 5036.6245
Mrs. Jones' Bill was $5036.63
(Rounded to the nearest 1/10)
A.
If you multiply the original equation by 3 you get -45x+3y=54, which is the exact same as A, therefore they have infinite solutions.
We find the base of the rectangles by taking the difference between the interval endpoints, and dividing by 2.
Base of rectangle = (6 - 2) / 2
= 2
The area of the first rectangle:
(4 - 2)f(4) = 2[4 + cos(4π)]
The area the second triangle:
(6 - 4)f(6) = 2[6 + cos(6π)]
Now just compute the two areas and combined them. That will give you the estimated under the curve.
To evaluate the midpoint of each rectangle, we take the midpoint of the base lengths of each rectangle. This midpoint is the x value. Then evaluate the function at that x value.
The midpoint of the first rectangle is x=3. Evaluate f(3).
The midpoint of the second rectangle is x=5. Evaluate f(5).
