Math Test Grade: Did I get screwed?

[oldoldman]

So I'm in Calculus 2 currently and on our second to last test we were doing tests on whether series converged or diverged. Two of the problems involved using the Integral Test to determine whether the 2 series converged or diverged, they were both eligible for the test so no problems there.

The problem came about when I did the test itself, for those of you who don't know the test will tell us whether or not the series converges or diverges but it will not tell us the number it converges to, therefor if you determine whether or not the integral converges the number you come to is irrelevant.

Both of the series had the sum http://upload.wikimedia.org/math/b/e...7cb04d4b6e.png where N -> http://upload.wikimedia.org/math/e/2...6098982278.png

Because all we needed to know was whether it converged to a number or diverged to infinity I took the integral from C to infinity of both functions where C was any constant. I found that the first converged to 1/ (C+2) which is a constant no matter what C is (excluding -2, which I noted alongside it with C =/= 2) . The second diverged, so the number I started the integration at was even more irrelevant.

The professor only gave me half credit for each problem because I didn't use the number 1 as the start of my integration. I tried to argue that the C itself didn't matter as long as it was a constant that defined the function the value of C did not matter, but he said that wasn't how he taught it so it wasn't worth full credit. The kicker is the way I did is how it is presented in the book.

So /bg/ I ask you, did I get screwed?

P.S. The point difference resulting from this could be the difference between 89 and 90 so it does matter.

[Vuitton]

What a douche. I am so glad I am in the social sciences. All of my professors are like, "yeah, when I calculate your final grade I take liberty to give you a higher score." Which usually meant they'd bump you up to the next grade level on a whim if they didn't dislike you.

[aalryn]

yes you did get screwed. If the value of the constant was given you should have used it to get a 'more correct' answer, but it seems you left that in variable form for a more general solution.

I could see loosing a few points for not fully completing the problem, but seeing how in math classes it's more 'the steps you took and your thought process' to actually 'getting the right final answer' your teacher is a hardass.


I have a minor in math (BS physics major), so I've taken calc 1-3, linear algebra, vector calc, diff eq, partial diff eq, discrete math, prob & stat, etc. basically any math you can take short of number theory and differential geometry. I can say that calc 2 was the hardest of all of the math classes i've taken. fuck trigonometric substitution especially since you'll NEVER use it. look that shit up in a table.

[Spekkio]

since you're working with a summation and not an integration it's impossible for over a finite boundary to have a divergent set. it's a given that sigma f(n) from n=1 to n=c is a constant so if it's convergent over n=c to n=infinity, it's convergent. easiest way to get a math prof is to tell him to back up his claim with a counterexample. caveat i haven't been in calc for a while so i'm a little rusty, but i'm fairly confident i'm not wrong.

[Ramor]

What a douche. I am so glad I am in the social sciences. All of my professors are like, "yeah, when I calculate your final grade I take liberty to give you a higher score." Which usually meant they'd bump you up to the next grade level on a whim if they didn't dislike you.

which is why i don't like any of the social sciences, and from the few classes i've taken as GECs i basically just lol at and go back to do real work like math and physics.

on a side note, it seems like you may have been screwed, should probably check it over with your TA first and then if all seems well check it with your prof., although depending on his area of study (you should probably find out what your prof's do for research beforehand, actually helps you know what they're likely to emphasize) he may just have worked with so many problems like your example that he's come across problems where that's an unacceptable substitution in terms of proving things and won't allow you to fall into the habit of doing it

[Gafgarionn]

"The main point is that the convergence of the series it not decided by any finite number of finite terms at the beginning, but only by the endless string of terms out to infinity."

This is from "Basic Training in Mathematics" by R. Shankar, and it's pretty obvious. Your teacher is retarded. Are you in college? If so, is he a TA or grad student? In any case, I'd go talk to a higher up who actually knows his shit.

[oldoldman]

"The main point is that the convergence of the series it not decided by any finite number of finite terms at the beginning, but only by the endless string of terms out to infinity."

This is from "Basic Training in Mathematics" by R. Shankar, and it's pretty obvious. Your teacher is retarded. Are you in college? If so, is he a TA or grad student? In any case, I'd go talk to a higher up who actually knows his shit.

He's the department chair. The class sizes aren't that huge so I was able to talk to him after the class but he insisted that the number we start from matters. When I asked why he couldn't back it up and said he had to go.

[Andarvi]

Dental school only requires me to go as far as Calc 1, which I took aeons ago, thus I do not have a friggin clue as to whether your answer or work is correct or not, however it seems you have at the very least a legitimate case to argue you are correct and/or deserve the 90. Even if he still insists you are incorrect, judging from the overwhelming support of your answer on this board by people who seem to know what they are talking about, you should at least swing him. Fuck, even if you were completely wrong, and based on the exam scores there was no curve, you should still get the friggin 3.7 instead of the 3.3. Fuck any professor who will not understand the significant difference between the two and not give you some slack over a measly point that in reality is probably a few decimal points, however in the long has a much more significant impact on your GPA.

[oldoldman]

The problem is there is really no where for me to take this to, I mean I guess I could go to the dean but I honestly doubt he would care much about 10% of one test.

[Trajan]

Bureaucrat Oldoldman you are technically correct, the best kind of correct. (can you tell I just read the futurama thread?)

[Trajan]

The problem is there is really no where for me to take this to, I mean I guess I could go to the dean but I honestly doubt he would care much about 10% of one test.

I've seen this happen before, where both sides have valid points but tbh there is really nothing you can do.

[HadesChubbs]

So I'm in Calculus 2 currently and on our second to last test we were doing tests on whether series converged or diverged. Two of the problems involved using the Integral Test to determine whether the 2 series converged or diverged, they were both eligible for the test so no problems there.

The problem came about when I did the test itself, for those of you who don't know the test will tell us whether or not the series converges or diverges but it will not tell us the number it converges to, therefor if you determine whether or not the integral converges the number you come to is irrelevant.

Both of the series had the sum http://upload.wikimedia.org/math/b/e...7cb04d4b6e.png where N -> http://upload.wikimedia.org/math/e/2...6098982278.png

Because all we needed to know was whether it converged to a number or diverged to infinity I took the integral from C to infinity of both functions where C was any constant. I found that the first converged to 1/ (C+2) which is a constant no matter what C is (excluding -2, which I noted alongside it with C =/= 2) . The second diverged, so the number I started the integration at was even more irrelevant.

The professor only gave me half credit for each problem because I didn't use the number 1 as the start of my integration. I tried to argue that the C itself didn't matter as long as it was a constant that defined the function the value of C did not matter, but he said that wasn't how he taught it so it wasn't worth full credit. The kicker is the way I did is how it is presented in the book.

So /bg/ I ask you, did I get screwed?

P.S. The point difference resulting from this could be the difference between 89 and 90 so it does matter.

You use some gay ass notation there.
the way we set it up looked completely different O.o still understood it, but weird.

yea, sounds alittle gay, but using 0 and 1 as a starting point can make a huge difference, whether or not it made a difference here. I'd say 1/2 off is extremely harsh.. maybe like -1 pt or something, but half? Guy needs to relax.

[Vuitton]

You basically have two choices. Pursue this until you're vindicated, and piss off this professor in the process, or leave things as they are, and if you have this professor in the future, you're more the wiser, and he won't have a grudge against you.

They do hold grudges. (I know, I am dating one.)

[Skjie]

You basically have two choices. Pursue this until you're vindicated, and piss off this professor in the process, or leave things as they are, and if you have this professor in the future, you're more the wiser, and he won't have a grudge against you.

They do hold grudges. (I know, I am dating one.)

This. Now you've learned a very valuable lesson about this professor and you won't make this mistake again. Once you've finished your degree, it won't matter a damn thing.

[HadesChubbs]

You basically have two choices. Pursue this until you're vindicated, and piss off this professor in the process, or leave things as they are, and if you have this professor in the future, you're more the wiser, and he won't have a grudge against you.

They do hold grudges. (I know, I am dating one.)

Rather, find out what courses he teaches, and decide whether or not in the future his opinion of you matters! If he isn't teaching any courses you need (and doesn't seem to desire to each any courses you plan to take), I'd follow up on this "screw"ing. If the A is worth it, do it. You're a student you have just as much right to challenge this grade as he has to give you the grade.

I had a prof. that would give extra credit points for standing face to face and arguing with him about a question(s) you had on the test (granted you had a valid arguement).

[Ramor]

actually one question, did you define C to be in the set of all real numbers? that may be his counterpoint if you didn't specify that

also, considering you've got k=1, doesn't that mean that the integral would need to start at 1 so that it would thereby include everything in the summation? it's 5:30, i may just be making things up it's been a long day

[HadesChubbs]

what was the exact question? I just passed calc2 with an 88 (fu test#2), I'm assuming since ur an 89/90 ur about the same lvl as me, maybe I can point out a mistake you missed? Understanding mistakes you made on previous tests helps so much in the future! (I had to take calc2 twice, and if I hadn't reviewed old tests I woulda phailed again)

[Nystul]

a bit of wisdom from someone that spent a long time in school, has a masters degree and has done a fair amount of teaching and grading tests:

the point of school is to learn various subjects as best as you can and to learn the most true and accurate information that is known in those subjects.

However, the point of graded material is to give the person grading it what they want.

If your teacher wants to insist that negative numbers don't exist, that vietnam bombed pearl harbor, and that each molecule is a tiny universe, then you better damn well play the game right and put that on a test. Learn the right thing, give the prof what they want even if it's wrong.you can fight this fight if you want, but even if this guy has great integrity, he'll be pissed at you and he'll have a very tough time not looking at your tests with a slightly more critical eye.

[Woozie]

You were right. If you're integrating from some constant to infinity, it doesn't matter what the constant is. You were right and he was wrong. It's as simple as that. The good thing about math is that things aren't usually up for discussion. Someone's usually right and everyone else is wrong.

Find a calculus book (any calculus book - or better yet, use multiple calculus books) and show him that this is the case (if you happen to be using Stewart 5th edition, refer to page 760). There's no way he can argue against a point where he's blatantly and obviously wrong. The fact that the department chair would even need clarification on this issue bothers me. My experience with math professors is that they're usually reasonable enough that if you show them that they are definitely wrong they'll change the grade.

Edit: My bad. I was wrong. See my post below.

[aalryn]

You were right. If you're integrating from some constant to infinity, it doesn't matter what the constant is. You were right and he was wrong. It's as simple as that. The good thing about math is that things aren't usually up for discussion. Someone's usually right and everyone else is wrong.

That would only be true if it was diverging. As it was converging it did matter what the initial value of the constant was, but leaving it in variable form would be fine in a general case. It just seems that your professor was looking for an indefinite answer. Kind of an ass to take away half of the points, but it happens.

My advanced mechanics (upper division kinematics) professor gave us a 3 question, 100 point test so 33 points per question. I missed a minus sign. I lost 10 points for a sign error. 90/100 on that test because of a minus sign. Some professor can be complete assholes.

Ugh a worse one. On my first vector calc test. we were given two vectors and had to say if they were parallel, perpendicular or orthogonal. I did all calculations and said they were orthogonal after calculating the x and y components were perpendicular and coplanar but the z component was on a different plane. I showed all calculations and said they were orthogonal. I lost points because I didn't write down in English the reason why when the question never said to explain. I still got an A in the class, but it put me in a place where I knew what to expect in the rest of the class.