If that sounds like it’d be helpful for you, all you need to do is sign up using the form below.

Note that you can also sign up for (or unsubscribe from) other automated site updates using the form. Just make sure that the updates you want to receive have checkmarks on them before you submit.

If you’re looking to stoke/assuage your fears about how the scoring table will turn out, you might find this useful. It’s a great way to see, at a glance, whether your impression of how hard the section were compared to your peers’ impressions.

This form is no longer accepting responses, but you can view the results here.

This survey is no longer accepting responses. You can see the results here.

]]>I also reformatted the official question lists at the end of each chapter—some of them were getting long and it was getting confusing to have multiple page numbers for each question. My new philosophy is that you know whether you have the tests in a book or printed out from your computer, and you know how to find #27 in section 4 of test 3 without me telling you which page it’s on. New official question listings look like this:

All the same information as the old tables in a more compact package.

One result of this is that books printed after these changes went live have slightly different paginations because some of the old end-of-chapter tables took up more than one page. I don’t anticipate this being a real problem for anyone, but if you’d like to download the new table of contents, that’s available for download in the Math Guide Owners Area, too.

]]>**Note:** If you purchased your book from the PWN store, you already have Math Guide Owner privileges through the account from which you made the purchase.

This survey is over, but if you’re curious, the results are below.

This is not really SAT specific or even particularly SAT useful, but I made the video above to help you create a basic quadratic formula program for your TI graphing calculator if that’s a thing you’d like to do.

If you’ve programmed things into your calculator before and don’t feel like watching a whole video, you can also just enter the program below. Make sure you’re careful with your quotation marks and parentheses, and always test the program with multiple quadratics to make sure it’s always giving you correct answers before you use it for anything important.

:Disp "AX^{2}+BX+C=0" :Prompt A :Prompt B :Prompt C :Disp "ROOTS:" :Disp (-B+√(B^{2}-4AC))/(2A) :Disp (-B—√(B^{2}-4AC))/(2A)

]]>

First, the equations in question.

**Vertex form of a parabola:** , where the vertex of the parabola is at .

**Standard circle equation:** , where a circle with radius *r* has its center at .

Say you’re given a parabola that’s not in vertex form and you need to put it in vertex form. How do you do that?

No calculator; grid-inThe parabola formed when the equation above is graphed in the

xy-plane has its vertex at . What is the value of ?

Completing the square isn’t the *only* way to solve this question, but I’d argue it’s the fastest. All we need to do to go from the given form to the vertex form is figure out which binomial square the part of the equation is the beginning of. With practice, this becomes second nature and you probably won’t need the rule, but the rule is that is the beginning of .* In this case, that means that is the beginning of .

Now, what do you get when you FOIL out ? You get . That’s not what we have above—we have instead. Luckily, we can do anything we want to the right side of the equation provided that we keep the equation balanced by doing the same thing to the left, so we can just add 10 to both sides!

From there, we’re almost done. Now we can convert the right side to the binomial square we wanted, and then get *y* by itself again to land in vertex form.

So, there you have it: the parabola in question has a vertex of . Since the question said the vertex was at , we know that , , and . So, 14 is the answer.

Let’s practice with a few more, shall we? **Try to do the following drill without a calculator. All three questions are grid-ins.**

* I’m intentionally limiting this post to scenarios where the leading coefficient in the square being completed is 1. So far, I have not seen an official question of this type where that is not the case.