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:
3/4
Step-by-step explanation:
Answer:
Domain:
3,6,12,18
Range:
5,7,9,10
Not a function
Step-by-step explanation:
X= Domain
Y= Range
The input 6 is pared with both 5 and 10
Answer:
a horse running around a race track and
a person running down a field to score a touchdown
DONT HAVE ENOUGH INFORMATION
the two graphs are proportional to time and
a dog jumping at a constant speed for 20min and
a truck passing through 4 cities at a constant speed are not proportional to time because they are constant
Step-by-step explanation:
Answer:
51 cm^2
Step-by-step explanation:
the formula for area of an icoselese triangle is
A = b * h / 2
h is a line from the angle where the 5 and 5 intersect to the middle of the third line
You can find h using the pythagoran theorm with the 5 being the hypotenuse and the a being half the third line
4^2 + b^2 = 5^2
16 + b^2 = 25
b = 3, so h = 3, so now
A = 8 * 3 / 2
A = 24 / 2
A = 12 cm^2
now we have the triangle, just multiply that by 2 (top and bottom)
12 * 2 = 24
sides
8 * 1.5 = 12
5 * 1.5 * 2 = 15
now add all of it
15 + 12 + 24 = 51
