Answer:
the distance between them is decreasing at a rate of 2 mph.
Step-by-step explanation:
List all given rates and the unknown rate.
Write the formula that relates the variables in the problem: x, y, and s.
There’s a right triangle in the diagram, so you use the Pythagorean Theorem:
For this problem, x and y are the legs of the right triangle, and s is the hypotenuse, so
Differentiate with respect to t.
Use the Pythagorean Theorem again to solve for s.
x = 0.4
y = 0.3
You can reject the negative answer because s obviously has a positive length. So s = 0.5.
Now you’ve got everything you need to substitute into the differentiation result and solve for ds/dt.
This negative answer means that the distance, s, is decreasing. Thus, when car A is 3 blocks north of the intersection and car B is 4 blocks east of the intersection, the distance between them is decreasing at a rate of 2 mph.
