Math Help Forum

Math Help Forum Feed Site Feed

Go Back   Math Help Forum > MHF Lounge > Chat Room
Reply
 
Thread Tools Display Modes
  #1  
Old November 4th, 2009, 11:07 PM
Bruno J.'s Avatar
Generous Contributor
 
Join Date: Jun 2009
Posts: 444
Country:
Thanks: 94
Thanked 154 Times in 137 Posts
Bruno J. has a spectacular aura aboutBruno J. has a spectacular aura about
Default Your best mathematical secrets...

So, as an addition to the How do YOU Study? thread, here is a thread where you can share your best mathematical secrets. What makes you good at calculus? What gives you an extra edge in algebra? What are your secret tricks?

Here is one of mine. It might not seem like much, but it's pretty good. If you all behave, you might get some more. When I'm attempting to solve a problem, I only write after I've thought long enough. This might seem obvious, but many, many people set out to solve problems and begin writing right away - this is like talking without thinking, only worse. When I break that rule, it's never pretty - it either results in a few pages of worthless scribble, in major depression, or in both.
Reply With Quote
Advertisement
 
  #2  
Old November 4th, 2009, 11:52 PM
Sampras's Avatar
Member
 
Join Date: May 2009
Posts: 235
Thanks: 29
Thanked 33 Times in 30 Posts
Sampras will become famous soon enough
Default

Use subconscious mind and lucid dreaming to solve problems.
Reply With Quote
  #3  
Old November 5th, 2009, 01:25 AM
Swlabr's Avatar
Senior Member
 
Join Date: May 2009
Posts: 270
Country:
Thanks: 28
Thanked 75 Times in 69 Posts
Swlabr will become famous soon enough
Default

Quote:
Originally Posted by Bruno J. View Post
So, as an addition to the How do YOU Study? thread, here is a thread where you can share your best mathematical secrets. What makes you good at calculus? What gives you an extra edge in algebra? What are your secret tricks?

Here is one of mine. It might not seem like much, but it's pretty good. If you all behave, you might get some more. When I'm attempting to solve a problem, I only write after I've thought long enough. This might seem obvious, but many, many people set out to solve problems and begin writing right away - this is like talking without thinking, only worse. When I break that rule, it's never pretty - it either results in a few pages of worthless scribble, in major depression, or in both.
I always re-write the problem first so I understand what it is asking...but on the whole, I would agree.

My "secret" would be if you are doing a lecture course always answer the tutorial questions. Always. If there are any you can't do: ask! Similarly, if you are reading a book do the questions! You can't help but understand if you are forced to think about stuff! (Although I am unsure if this theory holds for Analysis...)
Reply With Quote
  #4  
Old November 5th, 2009, 01:07 PM
Moo's Avatar
Moo Moo is offline
A Cute Angle
 
Join Date: Mar 2008
Location: P(I'm here)=1/3, P(I'm there)=t+1/3
Posts: 5,050
Country:
Thanks: 506
Thanked 2,916 Times in 2,399 Posts
Moo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond reputeMoo has a reputation beyond repute
Default

Like Swlabr, I always rewrite the problem. I guess a teacher once told us to do so in an exam, and ever since, I've adopted this method. And it's pretty useful.
The same way as I said in the topic "How do you study", I'd say it's a lot better if you've written the important thing yourself at least once.

Then I put the main ideas that can be directly taken from the text. And then think by writing, because I'm always messy, but I like to have everything just around.
__________________
Everything is possible. The impossible just takes longer.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

shinhidora production

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #5  
Old November 5th, 2009, 01:11 PM
e^(i*pi)'s Avatar
Generous Contributor
 
Join Date: Feb 2009
Location: West Midlands, England
Posts: 1,024
Country:
Thanks: 21
Thanked 413 Times in 403 Posts
e^(i*pi) is just really nicee^(i*pi) is just really nicee^(i*pi) is just really nicee^(i*pi) is just really nicee^(i*pi) is just really nice
Default

I write down what I know first - such as non-given constants/equations etc...

I also learn the basics and derive any complicated equations from the basic one
__________________


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #6  
Old November 5th, 2009, 04:20 PM
Administrator
 
Join Date: Oct 2005
Location: Earth
Posts: 2,208
Thanks: 389
Thanked 1,211 Times in 699 Posts
Jameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud of
Default

Similar to above.

Learn what formulas you can derive and those you can't. When I was in Calculus I and II there were tons of things to memorize but many of them could be reduced. Some things like Simpson's Rule or I just memorized the coefficients to save time. A great example of reducing memorizing is trig identities. Start with \sin^2(x)+\cos^2(x)=1 and the other two forms follow by dividing by sin(x) or cos(x). You all know that for sure but it was painful watching classmates memorize all three forms separately. Sometimes you can derive but it takes too long. Example: quadratic formula.

In algebra II I would use my calculator to test rules I wasn't sure about to double check. If anyone thinks about something like \sqrt{a+b}=\sqrt{a}+\sqrt{b} for a second it becomes obvious it's false.

Finally on AP math tests (or free response in general) if I couldn't get part A or a 5 part question and the next parts depended on the answer for A I would just pick something like 1. You can end up not knowing the idea of the problem at all but get most of the credit by thinking smart.
Reply With Quote
  #7  
Old November 5th, 2009, 04:28 PM
Senior Member
 
Join Date: May 2009
Location: New York
Posts: 415
Country:
Thanks: 10
Thanked 149 Times in 144 Posts
artvandalay11 has a spectacular aura aboutartvandalay11 has a spectacular aura about
Default

I wouldn't say the following makes me good at calculus but it definitely makes me much faster....


I try to avoid u-substitution at all costs when integrating. By this I mean I almost never actually write down let u= and then subsitute it back in so that I can see an obvious integration pattern.

I firmly believe that when learning calculus you should utilize and guess and test method in your head, and not write down u-subs. I've been integrating this way from the beginning, due to a fantastic teacher, and at the University level I was finishing my calc tests 25 minutes into the class. My professors were shocked and one even asked me where my u-sub was. I replied I don't need it, cuz there's your answer


Example: \int \cos (5x)dx

You should know that the answer is going to involve \sin
Moreover, it's going to involve \sin (5x) because there's no other way to get the 5 in there

Now take the derivative in your head, you'll realize that you'll be off by a factor of 5, so stick a \frac{1}{5} in front of your initial guess.


Obviously, I'm just not writing down the u-sub, but that's because you simply don't need to
__________________
Using elementary concubinary logic, you can easily show that the flumex is both semi-dependent and, even more importantly, quasi-invariant
Reply With Quote
  #8  
Old November 8th, 2009, 02:02 PM
Member
 
Join Date: Sep 2009
Posts: 94
Country:
Thanks: 5
Thanked 13 Times in 13 Posts
novice is on a distinguished road
Default

Quote:
Originally Posted by artvandalay11 View Post
I wouldn't say the following makes me good at calculus but it definitely makes me much faster....


I try to avoid u-substitution at all costs when integrating. By this I mean I almost never actually write down let u= and then subsitute it back in so that I can see an obvious integration pattern.

I firmly believe that when learning calculus you should utilize and guess and test method in your head, and not write down u-subs. I've been integrating this way from the beginning, due to a fantastic teacher, and at the University level I was finishing my calc tests 25 minutes into the class. My professors were shocked and one even asked me where my u-sub was. I replied I don't need it, cuz there's your answer


Example: \int \cos (5x)dx

You should know that the answer is going to involve \sin
Moreover, it's going to involve \sin (5x) because there's no other way to get the 5 in there

Now take the derivative in your head, you'll realize that you'll be off by a factor of 5, so stick a \frac{1}{5} in front of your initial guess.


Obviously, I'm just not writing down the u-sub, but that's because you simply don't need to
Some can do math in their sleep, and other will burn all midnight oil and still fail. A gift makes a whole world of a difference.

Why do engineers say they hate math? Hmmm!
Reply With Quote
  #9  
Old November 9th, 2009, 03:23 PM
Administrator
 
Join Date: Oct 2005
Location: Earth
Posts: 2,208
Thanks: 389
Thanked 1,211 Times in 699 Posts
Jameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud of
Default

Quote:
Originally Posted by artvandalay11 View Post
I wouldn't say the following makes me good at calculus but it definitely makes me much faster....


I try to avoid u-substitution at all costs when integrating. By this I mean I almost never actually write down let u= and then subsitute it back in so that I can see an obvious integration pattern.

I firmly believe that when learning calculus you should utilize and guess and test method in your head, and not write down u-subs. I've been integrating this way from the beginning, due to a fantastic teacher, and at the University level I was finishing my calc tests 25 minutes into the class. My professors were shocked and one even asked me where my u-sub was. I replied I don't need it, cuz there's your answer


Example: \int \cos (5x)dx

You should know that the answer is going to involve \sin
Moreover, it's going to involve \sin (5x) because there's no other way to get the 5 in there

Now take the derivative in your head, you'll realize that you'll be off by a factor of 5, so stick a \frac{1}{5} in front of your initial guess.


Obviously, I'm just not writing down the u-sub, but that's because you simply don't need to
I understand avoiding unnecessary writing to save time but I think the idea presented here is one that could hurt you more than help you. The example you gave is simple enough to do in your head, sure. Each intermediate step that is skipped on paper and done in your head adds more and more likelihood of an error in my opinion. Also one of the students I tutor constantly makes all kinds of errors from too skipping steps on paper so this makes me frustrated on the topic in general .

I'm curious, do you never use u-substitution when integrating or just for basic problems? Where do you break down and use it if so? What about for other substitutions like trig sub?
Reply With Quote
  #10  
Old November 9th, 2009, 04:06 PM
Member
 
Join Date: Sep 2009
Posts: 94
Country:
Thanks: 5
Thanked 13 Times in 13 Posts
novice is on a distinguished road
Default

Quote:
Originally Posted by Jameson View Post
I understand avoiding unnecessary writing to save time but I think the idea presented here is one that could hurt you more than help you. The example you gave is simple enough to do in your head, sure. Each intermediate step that is skipped on paper and done in your head adds more and more likelihood of an error in my opinion. Also one of the students I tutor constantly makes all kinds of errors from too skipping steps on paper so this makes me frustrated on the topic in general .

I'm curious, do you never use u-substitution when integrating or just for basic problems? Where do you break down and use it if so? What about for other substitutions like trig sub?
Jameson, you made me feel better. When I heard him saying there isn't any need for the u sub, I felt very ill thinking I am too dumb.
Reply With Quote
  #11  
Old November 9th, 2009, 04:07 PM
Senior Member
 
Join Date: May 2009
Location: New York
Posts: 415
Country:
Thanks: 10
Thanked 149 Times in 144 Posts
artvandalay11 has a spectacular aura aboutartvandalay11 has a spectacular aura about
Default

Quote:
Originally Posted by Jameson View Post
I understand avoiding unnecessary writing to save time but I think the idea presented here is one that could hurt you more than help you. The example you gave is simple enough to do in your head, sure. Each intermediate step that is skipped on paper and done in your head adds more and more likelihood of an error in my opinion. Also one of the students I tutor constantly makes all kinds of errors from too skipping steps on paper so this makes me frustrated on the topic in general .

I'm curious, do you never use u-substitution when integrating or just for basic problems? Where do you break down and use it if so? What about for other substitutions like trig sub?

In my experience tutoring calc, kids normally complain about being pressed for time, and then do simply integrals like the one above with u-sub, which drives me crazy.

I do write down trig subs and hyperbolic trig subs, but thats mainly because I don't encounter them too often (especially these days)

If I cannot get an integral after maybe 2 minutes of pure thought I might start fooling around with u-subs, but I really dont usually have to

For integration by parts I go straight to the tabular method

Normally my only u-subs come from problems with radicals in both numerator and denominator with different radicands, or something like that



If you truly have differentiation down, I feel "guessing and testing" would be quicker for many people who just weren't introduced to it
__________________
Using elementary concubinary logic, you can easily show that the flumex is both semi-dependent and, even more importantly, quasi-invariant
Reply With Quote
  #12  
Old November 9th, 2009, 04:22 PM
Administrator
 
Join Date: Oct 2005
Location: Earth
Posts: 2,208
Thanks: 389
Thanked 1,211 Times in 699 Posts
Jameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud ofJameson has much to be proud of
Default

Quote:
Originally Posted by artvandalay11 View Post
In my experience tutoring calc, kids normally complain about being pressed for time, and then do simply integrals like the one above with u-sub, which drives me crazy.

I do write down trig subs and hyperbolic trig subs, but thats mainly because I don't encounter them too often (especially these days)

If I cannot get an integral after maybe 2 minutes of pure thought I might start fooling around with u-subs, but I really dont usually have to

For integration by parts I go straight to the tabular method

Normally my only u-subs come from problems with radicals in both numerator and denominator with different radicands, or something like that



If you truly have differentiation down, I feel "guessing and testing" would be quicker for many people who just weren't introduced to it
I figured you did something like this. I agree that after a long time of doing certain types of problems you can get a feel for when it's time to write out all the steps and when it isn't. Many students think they reach that level too early though but that's what keeps me in business tutoring
Reply With Quote
  #13  
Old November 9th, 2009, 04:24 PM
Senior Member
 
Join Date: May 2009
Location: New York
Posts: 415
Country:
Thanks: 10
Thanked 149 Times in 144 Posts
artvandalay11 has a spectacular aura aboutartvandalay11 has a spectacular aura about
Default

I will say that I didnt use u-sub right from the get go. That's how my teacher taught it and looking back I couldnt be grateful enough. We later learned ths u-sub business. I was introduced to guess and test and since I, and the rest of my class, was so familiar with differentiation, it was no problem at all
__________________
Using elementary concubinary logic, you can easily show that the flumex is both semi-dependent and, even more importantly, quasi-invariant
Reply With Quote
  #14  
Old November 9th, 2009, 05:35 PM
Pinkk's Avatar
Member
 
Join Date: Mar 2009
Location: Uptown Manhattan, NY, USA
Posts: 158
Country:
Thanks: 45
Thanked 58 Times in 52 Posts
Pinkk will become famous soon enough
Default

Calculus just clicked with me. In high school I never studied for AP Calculus and I got a 100 in the class and a 5 on the AP exam. In college, I study, but not to the extent I know some students do. For me, I guess it's a combination of the subject just clicking with me and a diligence of doing the homework problems. Also, as I stated in the study thread, I always try to reword theorems, etc. in my own words and put the material into a context that makes sense to me. Sometimes textbook language can be quite dry, but I am pretty good at changing such dry language into a vivid context that is coherent and logical to me.
__________________
Everything under the sun is in tune, but the sun is eclipsed by the moon.
Reply With Quote
  #15  
Old November 10th, 2009, 10:19 AM
Newbie
 
Join Date: Nov 2009
Posts: 2
Thanks: 0
Thanked 0 Times in 0 Posts
gaby99 is on a distinguished road
Default

Like the above poster said, I also have the ability at times, to solve problems in my sleep
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off
Forum Jump


All times are GMT -7. The time now is 12:16 AM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.2.0 ©2008, Crawlability, Inc.
©2005 - 2009 Math Help Forum


Math Help Forum is a community of maths forums with an emphasis on maths help in all levels of mathematics.
Register to post your math questions or just hang out and try some of our math games or visit the arcade.