Answer:
x = 3
So,
PQ= 5
RS=6
Step-by-step explanation:
Hope it helps you.....
OK, so the graph is a parabola, with points x=0,y=0; x=6,y=-9; and x=12,y=0
Because the roots of the equation are 0 and 12, we know the formula is therefore of the form
y = ax(x - 12), for some a
So put in x = 6
-9 = 6a(-6)
9 = 36a
a = 1/4
So the parabola has a curve y = x(x-12) / 4, which can also be written y = 0.25x² - 3x
The gradient of this is dy/dx = 0.5x - 3
The key property of a parabolic dish is that it focuses radio waves travelling parallel to the y axis to a single point. So we should arrive at the same focal point no matter what point we chose to look at. So we can pick any point we like - e.g. the point x = 4, y = -8
Gradient of the parabolic mirror at x = 4 is -1
So the gradient of the normal to the mirror at x = 4 is therefore 1.
Radio waves initially travelling vertically downwards are reflected about the normal - which has a gradient of 1, so they're reflected so that they are travelling horizontally. So they arrive parallel to the y axis, and leave parallel to the x axis.
So the focal point is at y = -8, i.e. 1 metre above the back of the dish.
Answer:
You can draw three rectangles:
1- 28 * 1.
2- 14*2
3- 7*4
Step-by-step explanation:
We have a total area of 28. If we use only integer numbers, we can find all the divisors of 28. The possible rectangles will be organized with them, taking into account that the product of them, which means the area should be 28.
28 = 1*2*2*7
We can organize them as follows:
R1: 28 = 1*28
R2: 28 = 2*14
R3: 28 = 4*7
Finally, we can conclude that there are only three possibilities
1- 28 by 1.
2- 14 by 2
3- 7 by4
The perimeters will be:
Perimeter 1 = 2x1 + 2x28 = 58
Perimeter 2 = 2x2 + 2x14 = 32
Perimeter 3 = 2x4+2x7 = 22
Answer:
0.0007
Step-by-step explanation:
