Answer:
-2, 8/3
Step-by-step explanation:
You can consider the area to be that of a trapezoid with parallel bases f(a) and f(4), and width (4-a). The area of that trapezoid is ...
A = (1/2)(f(a) +f(4))(4 -a)
= (1/2)((3a -1) +(3·4 -1))(4 -a)
= (1/2)(3a +10)(4 -a)
We want this area to be 12, so we can substitute that value for A and solve for "a".
12 = (1/2)(3a +10)(4 -a)
24 = (3a +10)(4 -a) = -3a² +2a +40
3a² -2a -16 = 0 . . . . . . subtract the right side
(3a -8)(a +2) = 0 . . . . . factor
Values of "a" that make these factors zero are ...
a = 8/3, a = -2
The values of "a" that make the area under the curve equal to 12 are -2 and 8/3.
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<em>Alternate solution</em>
The attachment shows a solution using the numerical integration function of a graphing calculator. The area under the curve of function f(x) on the interval [a, 4] is the integral of f(x) on that interval. Perhaps confusingly, we have called that area f(a). As we have seen above, the area is a quadratic function of "a". I find it convenient to use a calculator's functions to solve problems like this where possible.
Answer:
A. R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.
Step-by-step explanation:
John is predicting test scores of students on the basis of their home work averages and he get the following regression equation
y=0.2 x +82.
Here, dependent variable y is the test scores and independent variable x is home averages because test scores are predicted on the basis of home work averages.
The coefficient of determination R² indicates the explained variability of dependent variable due to its linear relationship with independent variable.
We are given that correlation coefficient r= 0.82.
coefficient of determination R²=0.82²=0.6724 or 67.24%.
Thus, we can say that 67.24% of total variability in test scores is explained by its linear relationship with homework averages.
Also, we can say that, R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.
Answer:
okay so you would make a line straight across the middle of the spherical shape. The line that goes all the way across is the diameter. If you were to cut that line in half that would be the radius.
Step-by-step explanation:
The first circle shown in the picture provided would be an example of diameter, and the second circle would be an example of the radius. You could just make up a value, for example say the diameter is 10, the radius would be 5.
