Answer:
4
Step-by-step explanation:
The graph of the function
is
- concave upward, when

- concave downward, when

Find 
1.

2.

Now:
1. when
the graph of the function is concave upward and this is for

2. when
the graph of the function is concave downward and this is for

To find such critical points, you have to differentiate the function and let the derivative equal zero. Since this function is y written in terms of x, but implicitly, you must use implicit differentiation. Do you know how to do that?
Answer:
70 m
Step-by-step explanation:
AB makes a 30-60-90 triangle with the wall.
AC makes a 45-45-90 triangle with the wall.
In a 30-60-90 triangle, the short leg (opposite of the 30° angle) is half the hypotenuse.
In a 45-45-90 triangle, the legs are the same length.
So the distance between the left wall and the laser is 60/2 = 30 m.
The distance between the right wall and the laser is 40 m.
The total distance is therefore 70 m.
2 3/5 as improper fraction = 13/5