"22", "7" and "7,5" are the answers in order
So for this, you will be doing two different multiplications: 3 x 4 and √8 x √3.
3 x 4 = 12
√8 x √3 = √24
Now our result is 12√24, however, this can be simplified. Using the product rule of radicals (√ab = √a x √b), our simplification is such:
12√24 = 12√(8 x 3) = 12√(4 x 2 x 3) = 2 x 12√(2 x 3) = 24√6
In short, the answer is 24√6, or the first option.
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:
C
Step-by-step explanation:
A, B are wrong since 8,795 is a constant, it doesn’t change;
D is wrong since it is the starting cost, not total cost
Answer:
The y intercept is 5
Step-by-step explanation:
The slope intercept form of an equation is
y = mx+b where m is the slope and b is the y intercept
y = -3/2x+b
Substitute the point into the equation and solve for b
8 = -3/2(-2)+b
8 = 3+b
8-3 =b
5=b
The y intercept is 5
