Why would you need a calculator for this? I guess maybe for the trigonometry. Eh... no. Calculator doesn't help you. It's just that, see, the middle bottom angle there is 180-2x, eh? Well, the entirety of the left triangle is 180. So call the unknown N, it's 180 = x + 180 - 2x + N, you get N = x. Both are isocoles triangles. Therefore AD = BD = BC = 6.
True enough for that problem, but often they'll ask you to solve trig questions that require previous memorization of what the sine and cosine of 60o are, etc., etc. If it's been years since you committed those babies to memory, you're pretty much farked. In my math-monkey island analogy, I'd be coconutted to death. Unless there's a way of deriving those facts on the fly? I'm open to suggestions. The best I've come up with is that you must, at the very least, memorize what a 30-60-90 and 45-45-90 triangle "look like" in terms of side lengths.
This is turning into The Compendium Guide to the GRE.
Ah, I think there is a way of doing it. Whatchamacallit, Taylor Polynomials. Not that I remember how to do them, but I think you can derive the solutions that way. It's the way calculators work, too. Anyway, what this all is testing is your ability not to memorize methods more than your ability to abstractly problem solve. I had no bloody clue what an 'addition table' was, but I had no problem rationalizing how to think through it because it seemed to be a logical solution to the problem at hand. Maybe it's my engineering training that does that. Actually, that's probably the main distinction between university and something like a technical college: a technical school teaches you specific skillsets. A university teaches you a base way to think so that you can apply it to multiple scenerios. I think that sort of general understanding is what the test was attempting to figure through: not if you can jump through the hoops of specific formulas, but if you can think in a general mathematical way in order to reason through solutions even of problems you've not been exposed to. The triangle one is a perfect example of that.
Though I must say, I wasn't all that great at higher level mathematics, simply because I'm better at the directly applied formulae (like in dynamics) rather than the abstract thinking that, say, multiple variable differential equations *shudder* require. That sort of stuff taxed my upper mental limit. Though, ironically, in things like languages and translation I'm not a 'grammar' type translator, and don't think step by step, but am always trying to contextualize and think here there and everywhere. Hm. Anyway, pure mathematics were never my strong suit. The basic calculus which you used to, say, derive the equations of velocity... that stuff was fun. But when it got to stuff that's difficult to visualize, I lost it. (Though I must say, some of the basic stuff can be a heck of a lot of fun... like using integration to get the formula for the area of a triangle. For simplicity, if you take a right angle one, and put the angle on the origin of an x/y grid... say, make the triangle A high and B wide... well, derive the sloped line (which would then be... y=(A/-B)x + A) ... A/B being the slope) you get integration of this, which would be something like integral (y) = .5(A/-B)x^2 +Ax = (0.5A/-0.5B)x^2 + Ax... from x=0 to x=B, therefore...
integral = area = .5(A/-B)B^2 +AB = -0.5AB + AB = .5AB... therefore, as we've been told since children, area of a triangle is 0.5A*B. Cool, eh? I thought that awesome when I first learned it.
What's a GRE, by the way? I assume it means something like General Requirement Exam. We don't have anything like that in Canada that I'm aware of.
