PDA

View Full Version : Help on Exam 1

amberuco
10-03-2003, 10:24 AM
I am studying for the exam in November, and would appreciate some help. I seem to be having the most problems with identifying graphs of derivatives, second derivatives. Does anyone have any tips for me on how to identify these easily? Also how important is this concept in the big scheme of things?

Blue Like Jazz
10-03-2003, 11:21 AM
You'll probably have one question on it. If the passing score is 23 out of 40, it's a pretty easy guaranteed 1/23rd of the way there.

Here's one tip: Look for places where curves cross the x-axis. They should correspond to max or mins on the other graph.

Mauve'Bib
10-03-2003, 01:43 PM
I don't really have tips - just think it through and, with a little practice, it's easy.

I'd definitely learn it because, although only one or two questions, some of these type from prior exams are questions that you can answer quickly if you know what you're doing. JMO

Summer
10-03-2003, 03:09 PM
I would know this too. It is kind of hard to explain without looking at a graph, but I would know this as well. THere are easy and hard questions on the exam...if this is on it, usually it is one of the easy questions. You don't want to throw those away.

Go over it again, and look at lots of diagrams. Do you have a text book, or are you just using a study manual. If you don't have a text, and don't wish to buy one, you probably can easily find one in the library (there are probably tons - especially a university library)

Westley
10-04-2003, 05:46 PM
If you are looking at a graph of a function and its derivative, then the first derivative has to be zero when the function hits a max or min (this should clear out at least a couple wrong answers). Then, just map out a couple points where the derivative is positive, and make sure that the original graph is increasing at those points. Then, points where the derivative is negative, and the graph has to be decreasing.

If it's a function and its second derivative, then look for points where the second derivative is zero - that's where it switches between concave upward and downward.

If you get stuck and are trying to remember the rules (second derivative negative means concave up?), just graph a function you know well (y = x^2) and look at its second derivative and how it looks.

amberuco
10-05-2003, 09:43 AM
Thanks everyone for your input. I did the questions again that I was having problems on and I could identify them just fine. Thanks!!!

abacustwo
10-05-2003, 09:21 PM
Actually, if the second derivate is positive then the function is concave upward. On the flip side, if the second derivate is negative the function is concave downward.