Answer:
C.
Step-by-step explanation:
as 0.05 is 1/10 of a number, multiplying 0.05 by 10 will give you the number that when divided by 10 will give you 0.05. Hence just multiply 0.05 by 10 and you get 0.5.
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:
The number of cookies in the jar is 7.
If we include the 5 cookies from the tray in the jar the total number of cookies would be 5 + 7 = 12
Step-by-step explanation:
<em>Consider the number of cookies in the jar as 'x'. Hence the equation formed would be:-</em>
7(x) + 5 = 54
7x + 5 = 54
7x = 54 - 5
7x = 49
x = 
x = 7
The number of cookies in the jar is 7.
If we include the 5 cookies from the tray in the jar the total number of cookies would be 5 + 7 = 12
<em>Hope this helps.</em>
She can move the decemal place 2 places to the right because a centimeter is 100 times smaller than a meter. so it would be 785 centimeters
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