Answer:
see explanation
Step-by-step explanation:
the equation of a circle in standard form is
(x - h)² + (y - k )² = r²
where (h, k ) are the coordinates of the centre and r is the radius
given
x² + y² - 8x + 8y + 23 = 0
collect the x and y terms together and subtract 23 from both sides
x² - 8x + y² + 8y = - 23
using the method of completing the square
add ( half the coefficient of the x / y terms )² to both sides
x² + 2(- 4)x + 16 + y² + 2(4)y + 16 = - 23 + 16 + 16
(x - 4)² + (y + 4)² = 9 ← in standard form
with centre = (4, - 4 ) and r = = 3
this is shown in graph b
value of at x=8 is
.
<u>Step-by-step explanation:</u>
here we need to evaluate 12 + x to the power of 4 - 6 when x = 8 or , where x=8 . Let's find out:
⇒
Putting x =8 :
⇒
Splitting 8 to power 4 into 8 to power 2 ( 2 times )
⇒
⇒
⇒
⇒
⇒
Therefore , value of at x=8 is
.
Answer:
a)
b) r =-0.932
The % of variation is given by the determination coefficient given by and on this case
, so then the % of variation explained by the linear model is 86.87%.
Step-by-step explanation:
Assuming the following dataset:
Monthly Sales (Y) Interest Rate (X)
22 9.2
20 7.6
10 10.4
45 5.3
Part a
And we want a linear model on this way y=mx+b, where m represent the slope and b the intercept. In order to find the slope we have this formula:
Where:
With these we can find the sums:
And the slope would be:
Nowe we can find the means for x and y like this:
And we can find the intercept using this:
So the line would be given by:
Part b
For this case we need to calculate the correlation coefficient given by:
So then the correlation coefficient would be r =-0.932
The % of variation is given by the determination coefficient given by and on this case
, so then the % of variation explained by the linear model is 86.87%.