Answer:
160 pages.
Step-by-step explanation:
That is 125 - 0.20 * 125
= 125 - 25
= 160 pages.
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.
96
/ \
8 • 12
/ \ / \
4 • 2 • 4 • 3
/ \ / \
2 2 2 2
96 is 2•2•2•2•2•3 or 2^5•3
Step-by-step explanation:
-x² + 2x + 48
-x² - 6x + 8x + 48
-x( x + 6 ) + 8( x + 6)
( x + 6 ) ( -x + 8 )
Answer:
8 different choices
Step-by-step explanation:
With or without antibrake=2 ways
With or without player=2ways
With or without sunroof=2 ways
Total number of ways=2×2×2=8 ways
