This response is based upon your having had some background in calculus. "dx" is not introduced before that.
Take a look at the sample function y = f(x) = x^2 + 9. Here x is the independent variable; the dependent variable y changes with x.
Now, for a big jump: we consider finding the area under a curve (graph) between x = a and x = b. We subdivide that interval [a,b] into n vertical slices of area. Each of those slices has its own area: f(x)*dx, where dx represents the width of such subarea. f(x)*dx is the actual subarea. To find the total area under the curve f(x) between x= a and x = b, we add up all of these individual subareas between x = a and x = b. Note that the subinterval width is
b-a
dx = ---------- , and that dx becomes smaller and smaller as the number of
n subintervals increases.
Once again, this all makes sense only if you've begun calculus (particularly integral calculus). Do not try to relate it to earlier math courses.
Answer:
180,000 people
Step-by-step explanation:
2/5= 0.4
0.4x450,000=180,000
Answer:
2x + 3y = 10, 3y = 18 (in both cases, for each input x, there is exactly one output y.
Step-by-step explanation:
3y = 10 - 2x, or y = (1/3)(10 - 2x) Yes, this is a function.
4x = 16 → x = 4 NOT a Function, because for x = 4 there are an infinite number of possible y -values
2x - 3 = 14 → 2x = 17 → x = 17/2 Not a function. See reason given above.
3y = 18 → y = 6 Function
2x = 14.6 → x = 7.3 Not a function. See reason given above
Answer: The tree was 27 feet tall
Step-by-step Explanation: First of all Sally was standing 30 feet away from the tree and she looks up at an angle of elevation of 38 degrees to the top of the tree. With this bit of information we can determine that a right angled triangle has been formed with the reference angle as 38 degrees, the side facing it as h (the height of the tree) and the adjacent side as 30. We shall apply the trigonometric ratio as follows;
Tan 38 = opposite/adjacent
Tan 38 = h/30
0.7813 = h/30
0.7813 x 30 = h
23.4 = h
We remember at this point that Sally’s eyes were 4 feet above the ground. What we have just calculated is the height of the tree from “4 feet above the ground” (where her eyes were). Hence the actual height of the tree is calculated as 23.4 plus 4 which gives us 27.4
Therefore the tree was 27 feet tall (approximately to the nearest foot)
