Maths Help Please!! :(

Test Preparation SAT Preparation
1

<p>i have a couple of nasty questions </p>

<p>( a quadratic function facing downwards )</p>

<ul>
<li>The quadratic function graphed above has equation
f(x) = a - x^2. Which of the following must be true?
(A) a > 0
(B) a < 0
(C) a is even.
(D) a is odd.
(E) a is the square of an integer.</li>
</ul>

<p>( a right angle triangle with a and b as length and with and 20 as hypotenuse)
FIGURE NOT DRAWN TO SCALE --</p>

<p>**Which of the following inequalities is true about the
lengths a and b of the sides of the triangle above?
(A) 0=(a+b)2 <20
(B) 20 = (a+b)2 < 40
(C) 40 = (a+b)2 < 100
(D) 100 = (a+b)2 < 400
(E) 400 = (a+b)2</p>

<p>***A sphere has radius 6 inches. What is the
volume, in cubic inches, of the smallest cube that can
contain the entire sphere?</p>

<p>( i would really appreciate your feedback) :)</p>

2

<p>anyone ?? oh come on! pleeaassse :(</p>

3

<p>For the first problem, you need to describe the graph better, because
f(x) = a - x^2 faces downward no matter what a is. The size of a will determine how far above or below the x-axis the graph is.</p>

<p>I don't get the second problem. What do you mean, (a+b)2? Do you mean squared? In any case, you know that a + b > 20 by the triangle inequality and a^2 + b^2 = 400 by the Pythagorean theorem, and you work from there.</p>

<p>The smallest cube containing a sphere of radius 6 has side 12, so its volume is 12 * 12 * 12.</p>