Given the vertex of the parabola at point (2, -3):
The quadratic function in vertex form is:
f(x) = (x - 2)^2 - 3
where the vertex (h, k) is the minimum point = (2, -3).
#3
A(x) = 1000(1+.17)x
because the 17 percent would have to be changed to a decimal form
Start with a proportion, to get the number of degrees in 30 seconds:
(150 degrees / 5 seconds) = ('D' degrees / 30 seconds) .
Cross multiply the proportion: (150 x 30) = 5 x D
4,500 = 5 x D
Divide each side by 5 : 900 = D
The globe turns 900 degrees in 30 seconds.
How many rotations is that ?
Each rotation is 360 degrees.
So 900 degrees is
(900 / 360) = <em>2.5 rotations</em> in 30 seconds.
This is rationalising the denominator of an imaginary fraction. We want to remove all i's from the denominator.
To do this, we multiply the fraction by 1. However 1 can be expressed in an infinite number of ways. For example, 1 = 2/2 = 3/3 = 4n^2 / 4n^2 (assuming n is not zero!). Let's express 1 as the complex conjugate of the denominator, divided by the complex conjugate of the denominator.
The complex conjugate of (3 - 2i) is (3 + 2i). Then do what I just said:
4/(3-2i) * (3+2i)/(3+2i) = 4(3+2i)/(3-2i)(3+2i) = (12+8i)/(9-4i^2) = (12+8i)/(9+4) = (12+8i)/13
This is the answer you are looking for. I hope this helps :)
