If your directrix is a "y=" line, that means that the parabola opens either upwards or downwards (as opposed to the left or the right). Because it is in the character of a parabola to "hug" the focus, our parabola opens upwards. The vertex of a parabola sits exactly halfway between the directrix and the focus. Since our directrix is at y = -2 and the focus is at (1, 6) AND the parabola opens upward, the vertex is going to sit on the main transversal, which is also the "line" the focus sits on. The focus is on the line x = 1, so the vertex will also have that x coordinate. Halfway between the y points of the directrix and the focus, -2 and 6, respectively, is the y value of 2. So the vertex sits at (1, 2). The formula for this type of parabola is
where h and k are the coordinates of the vertex and p is the DISTANCE that the focus is from the vertex. Our focus is 4 units from the vertex, so p = 4. Filling in our h, k, and p:
. Simplifying a bit gives us
. We can begin to isolate the y by dividing both sides by 16 to get
. Then we can add 2 to both sides to get the final equation
, choice 4 from above.
Answer:
9^2/256
Exact form is 81/256
Decimal form is 0.31640625
Step-by-step explanation:
Raise 9 to the power of 2.
81/256
The result can be shown in multiple forms.
Exact Form:
81/256
Decimal Form:
0.31640625
Answer:
x=5/2
Step-by-step explanation:
Calculate, rewrite, remove the paretheses
Collect the like terms
Swap sides 75=30x swap to 30x=75
Then divide both sides
I believe the answer is letter A
Answer:
Step-by-step explanation:
y=sqrt(x-7)+3 is a transformed from the parent function y=sqrt(x) by the following:
right 7 units
up 3 units