Answer:
Step-by-step explanation:
ignore the "at the instant the man is 30 feet away" part, set it as X and the man's shadow as Y.
Similar triangles so we can do
.
Solve for it we get 44y = 6x
Differentiate relative to time t, we get 44y' = 6x'.
change in x (x') is equal to 5. And we get the answer y' =
.
the
ft/sec is the rate of which the length of the shadow is changing. add 5 to it for the rate of the tip of his shadow moving away from the tower.
A coordinate grid is very handy when it comes to drawing geometric shapes such as triangles. Let's create an example triangle ABC with the locations
A = (2,3)
B = (9,5)
C = (4,-10)
Plot those points and connect the dots. That forms triangle ABC. We can translate triangle ABC to any other position we want. Let's say we want to shift it 2 units to the left. That means we subtract 2 from each x coordinate while keeping the y coordinates the same. Therefore
A' = (0, 3)
B' = (7, 5)
C' = (2,-10)
Plot triangle A'B'C' and you should see that this is a shifted copy of triangle ABC.
The rotation rules are a bit more complicated, and it depends where you place the center of rotation; however, it is possible to use coordinate math like done above.
Luckily the reflection rules over the x or y axis are fairly simple. If we reflect over the x axis, then we flip the sign of the y coordinate. Or if we wanted to reflect over the y axis, we flip the sign of the x coordinate.
Example: A' = (0,3) reflects over the x axis to get A'' = (0, -3)
To answer this, we need to see the polynomial. Descending order is in a way that the first term of the polynomial will be three, the second (in descending order, two....and so on).
420t+20t3-210t2
In descending order is:
20t^3 - 210t^2 + 420t
So, the option is number two.
Answer:
B
Step-by-step explanation:
Supplementary angles sum to 180°
If one angle is 77°, then the other angle is
180° - 77° = 103° → B