# January 2013 I Math (plane and sphere, math and academic team)

<p>Let's discuss the math section! What did people get for the plane intersecting with the sphere at point p?</p>

<p>4? wasn’t sure about that one!</p>

<p>I said that it was 2 radii, but it seemed too easy. thinking back, there are 6 perpendicular radii, 4 of them would be in the plane so I’m pretty confident in my answer (2). </p>

<p>The math/academic team question clicked really easily for me for some reason, there were 11 only in one team and 9/10 on each team so I said that had 5 and 6 single team people and 4 on both teams.</p>

<p>Plane one had to be two, because the only way to be perpendicular to the plane cutting through the center of the sphere is the radii from the top going to the center and from the bottom going to the center.</p>

<p>I answered 2 as well. Don’t see any other logical choice.</p>

<p>I got 4 too at legitimately the last second possible lol. I completely missed the plane question darn!</p>

<p>I said more than four but it’s supposed to be two. I didn’t realize actual planes don’t have edges that can be perpendicular to stuff.
Good news is that’s the only question I know of so far that I missed.</p>

<p>Anyone remember the parabola question? I remember being only about 75% sure on that one.</p>

<p>The question regarding a? I said that a>1</p>

<p>I don’t really remember the question or my answer to be honest. Does anybody remember the specifics in that question?</p>

<p>I don’t remember exactly but I think you had to notice that the parabola was steeper than just a 1x^2 function so a in ax^2 has to be greater than one? Am I completely wrong or?</p>

<p>It gave you a parabola and ax^2 + bx + c and you had to say what a equaled</p>

<p>I think the vertex was -2,-1</p>

<p>Not too sure what I answered there.</p>

<p>How was a = 1??</p>

<p>I got 25 for the kids and the train one…</p>

<p>What did you all get on the table cloth question? I left it blank…
Options were like, 64 - 8pi etc.</p>

<p>Does anyone remember what the vertex of the parabola was?</p>

<p>(-2,1) I think
@keepincalm I got 120 for kids and 64pi-16</p>

<p>Kids and train one, just 5! = 120 and the vertex was (-2, -1). I was also unsure about the parabola, but CC discussions site-wide seem to be coming into consensus that it was a>1</p>