Answer:
The equation of the quadratic graph is f(x)= - (1/8) (x-3)^2 + 3 (second option)
Step-by-step explanation:
Focus: F=(3,1)=(xf, yf)→xf=3, yf=1
Directrix: y=5 (horizontal line), then the axis of the parabola is vertical, and the equation has the form:
f(x)=[1 / (4p)] (x-h)^2+k
where Vertex: V=(h,k)
The directix y=5 must intercept the axis of the parabola at the point (3,5), and the vertex is the midpoint between this point and the focus:
Vertex is the midpoint between (3,5) and (3,1):
h=(3+3)/2→h=6/2→h=3
k=(5+1)/2→k=6/2→k=3
Vertex: V=(h,k)→V=(3,3)
p=yf-k→p=1-3→p=-2
Replacing the values in the equation:
f(x)= [ 1 / (4(-2)) ] (x-3)^2 + 3
f(x)=[ 1 / (-8) ] (x-3)^2 + 3
f(x)= - (1/8) (x-3)^2 + 3
The answer is negative, because the first number is negative.
さたはたはたはたはたはたはたはたはたはたしたはあらさたはたはてはありはあはあはあらありあは
The Amazon rainforest is gradually being destroyed by pollution and agricultural and industrial development. For simplicity, suppose that each year, 10% of the remaining forest is destroyed. Assume, also for simplicity, that the present area of the Amazon rainforest is 1,200,000 square miles.
1.a) What will the area of the forest be after 1 year of this destruction process?
1.b) What will the area of the forest be after 2 years of this destruction process?
2) Make a graph showing your results from Question 1 and continuing through 5 years of the destruction process. Include the present situation as a point on your graph.
3) Find a rule for how much rain forest will remain after X years. That is, express the area of the rain forest as a function of X.