The answer would be (A) <span>(x − 4)^2 + (y − 4)^2 = 16
</span>
(tan²(<em>θ</em>) cos²(<em>θ</em>) - 1) / (1 + cos(2<em>θ</em>))
Recall that
tan(<em>θ</em>) = sin(<em>θ</em>) / cos(<em>θ</em>)
so cos²(<em>θ</em>) cancels with the cos²(<em>θ</em>) in the tan²(<em>θ</em>) term:
(sin²(<em>θ</em>) - 1) / (1 + cos(2<em>θ</em>))
Recall the double angle identity for cosine,
cos(2<em>θ</em>) = 2 cos²(<em>θ</em>) - 1
so the 1 in the denominator also vanishes:
(sin²(<em>θ</em>) - 1) / (2 cos²(<em>θ</em>))
Recall the Pythagorean identity,
cos²(<em>θ</em>) + sin²(<em>θ</em>) = 1
which means
sin²(<em>θ</em>) - 1 = -cos²(<em>θ</em>):
-cos²(<em>θ</em>) / (2 cos²(<em>θ</em>))
Cancel the cos²(<em>θ</em>) terms to end up with
(tan²(<em>θ</em>) cos²(<em>θ</em>) - 1) / (1 + cos(2<em>θ</em>)) = -1/2
Because the parabola opens down and the vertex is at (0, 5), we conclude that the correct option is:
y = -(1/8)*x² + 5.
<h3>
Which is the equation of the parabola?</h3>
The relevant information is that we have the vertex at (0, 5), and that the parabola opens downwards.
Remember that the parabola only opens downwards if the leading coefficient is negative. Then we can discard the two middle options.
Now, because the parabola has the point (0, 5), we know that when we evaluate the parabola in x = 0, we should get y = 5.
Then the constant term must be 5.
So the correct option is the first one:
y = -(1/8)*x² + 5.
If you want to learn more about parabolas:
brainly.com/question/4061870
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