Question

Given y = a(x - h)^2 + k, p = A. a B. 4a C. 1/4a

Answer 1

9514 1404 393

Answer:

  C.  1/(4a)

Step-by-step explanation:

We assume you're comparing the vertex form ...

  y = a(x -h)^2 +k

to the form used to write the equation in terms of the focal distance p.

  y = 1/(4p)(x -h)^2 +k

That comparison tells you ...

  a = 1/(4p)

  p = 1/(4a) . . . . . . multiply by p/a; matches choice C

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Additional comment

When using plain text to write a rational expression, parentheses are needed around any denominator that has is more than a single constant or variable. The order of operations requires 1/4a to be interpreted as (1/4)a. The value of p is 1/(4a).

When rational expressions are typeset, the fraction bar serves as a grouping symbol identifying the entire denominator:

  $p=\dfrac{1}{4a}$