F(x) = 18-x^2 is a parabola having vertex at (0, 18) and opening downwards.
g(x) = 2x^2-9 is a parabola having vertex at (0, -9) and opening upwards.
By symmetry, let the x-coordinates of the vertices of rectangle be x and -x => its width is 2x.
Height of the rectangle is y1 + y2, where y1 is the y-coordinate of the vertex on the parabola f and y2 is that of g.
=> Area, A
= 2x (y1 - y2)
= 2x (18 - x^2 - 2x^2 + 9)
= 2x (27 - 3x^2)
= 54x - 6x^3
For area to be maximum, dA/dx = 0 and d²A/dx² < 0
=> 54 - 18x^2 = 0
=> x = √3 (note: x = - √3 gives the x-coordinate of vertex in second and third quadrants)
d²A/dx² = - 36x < 0 for x = √3
=> maximum area
= 54(√3) - 6(√3)^3
= 54√3 - 18√3
= 36√3.
About 1920, just find the volume by multiplying length times width times height
and divide that by the 1-inch cubes. hope this helps
Answer:
1. Median = 10.1
2. A. The median represents the center.
3. D. The mode(s) can't represent the center because it (they) is(are) not a data value.
Step-by-step explanation:
Mean of a sample = sum of the samples/no of the samples
Samples in increasing order:
9.8
9.8
9.9
10.1
10.4
10.6
11.1
Mode is the sample with highest frequency.
Median is the middle entry of the data.
Mean = (9.8 + 9.8 + 9.9 + 10.1 + 10.4 + 10.6 + 11.1)/7
= 717/7
= 10.243
Median = 10.1
Mode = 9.8 because it has the highest frequency of 2
