Answer:
A) reflection across the y-axis
Step-by-step explanation:
If
, then this says that two
-coordinates are equal for opposite values of
.
Let
a point on
.
Then
.
We also know that
and therefore
is also a point on the graph.
If you graph [/tex](-a,b)[/tex] and
you will see they are symmetrical to each about the
-axis.
Example if given both
and
, then
. This means both (2,3) and (-2,3) are points on the graph.
Here is what those two points look like on a Cartesian Plane (please see graph in picture).
Answer:
45
Step-by-step explanation:
a.
is a joint density function if its integral over the given support is 1:


so the answer is yes.
b. We should first find the density of the marginal distribution,
:


Then

or about 0.2019.
For the other probability, we can use the joint PDF directly:

which is about 0.7326.
c. We already know the PDF for
, so we just integrate:
![E[Y]=\displaystyle\int_{-\infty}^\infty y\,f_Y(y)\,\mathrm dy=\frac15\int_0^\infty ye^{-y/5}\,\mathrm dy=\boxed5](https://tex.z-dn.net/?f=E%5BY%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20y%5C%2Cf_Y%28y%29%5C%2C%5Cmathrm%20dy%3D%5Cfrac15%5Cint_0%5E%5Cinfty%20ye%5E%7B-y%2F5%7D%5C%2C%5Cmathrm%20dy%3D%5Cboxed5)
Answer:
C. 500 + 300 + 50 + 10 + 7
Step-by-step explanation:
Which expression represents the number 867?
A. 80 + 60 + 70
B. 800 + 6 + 7
C. 500 + 300 + 50 + 10 + 7
D. 500 + 300 + 60 + 70
Checking the answer choices by adding the expression
A. 80 + 60 + 70
= 210
No correct
B. 800 + 6 + 7
= 813
Not correct
C. 500 + 300 + 50 + 10 + 7
= 867
Correct
D. 500 + 300 + 60 + 70
= 930
Not correct
Therefore option C. 500 + 300 + 50 + 10 + 7 is the correct answer
Answer:
80 represents the monthly fees and 50 represents the fixed one-time fee to store the bike at the train station.