Freeman Posted July 19, 2004 Share Posted July 19, 2004 What is the code in mathematica for sigma? Link to comment Share on other sites More sharing options...
Dave Posted July 19, 2004 Share Posted July 19, 2004 Sum[] I think. Just google for it or look in the online help. Link to comment Share on other sites More sharing options...
Freeman Posted July 19, 2004 Author Share Posted July 19, 2004 How do I put a limit on it? Link to comment Share on other sites More sharing options...
Freeman Posted July 19, 2004 Author Share Posted July 19, 2004 I wanna plug in: [math]\sum_{m=2}_{n=2} m\times n[/math] Link to comment Share on other sites More sharing options...
bloodhound Posted July 19, 2004 Share Posted July 19, 2004 is that sum rite? how can u have two index in one sum. you probably mean a double sum Link to comment Share on other sites More sharing options...
Freeman Posted July 19, 2004 Author Share Posted July 19, 2004 Yes! That's it! How do I have one of those! Link to comment Share on other sites More sharing options...
bloodhound Posted July 19, 2004 Share Posted July 19, 2004 cant help u there. i dont use mathematica. i use maple Link to comment Share on other sites More sharing options...
Dave Posted July 19, 2004 Share Posted July 19, 2004 Just use a nested sum (i.e. Sum[sum[]]) Link to comment Share on other sites More sharing options...
Dave Posted July 19, 2004 Share Posted July 19, 2004 Btw, LaTeX code for double sums: [math]\sum_{m=2}\sum_{n=2} m\times n[/math] Link to comment Share on other sites More sharing options...
Freeman Posted July 20, 2004 Author Share Posted July 20, 2004 Hey, is it possible to have a sigma equation to figure out all possible solutions for a problem? What would the code of that be? Link to comment Share on other sites More sharing options...
Cap'n Refsmmat Posted July 20, 2004 Share Posted July 20, 2004 How come when I mouse over latex it gives me that "link hand" that you get over links? And why doesn't it do anything if I click on it? Link to comment Share on other sites More sharing options...
Freeman Posted July 20, 2004 Author Share Posted July 20, 2004 Because that's the way it works... it's every premade image put on a site with a lot of bandwidth, then sent here. I think that's how it works... Link to comment Share on other sites More sharing options...
Cap'n Refsmmat Posted July 20, 2004 Share Posted July 20, 2004 I just checked. It's made as soon as you post it, and the pic stored on Blike's website. Link to comment Share on other sites More sharing options...
Freeman Posted July 20, 2004 Author Share Posted July 20, 2004 Is there a sigma equation that gives a set as an answer for mathematica??? Link to comment Share on other sites More sharing options...
Dave Posted July 21, 2004 Share Posted July 21, 2004 Come again? Link to comment Share on other sites More sharing options...
Freeman Posted July 22, 2004 Author Share Posted July 22, 2004 Okay, allow me to restate it. The sigma code adds the solutions togather fopr the answer, e.g. [math]\sum_{q=0}^n (q+1)^2[/math] if n was 2 the answer is 5. However, is there an equation which makes the answer to this problem a set? So it would be {1,4} rather than 5. If an equation exists, what would it be on mathematica? Link to comment Share on other sites More sharing options...
Freeman Posted July 22, 2004 Author Share Posted July 22, 2004 Like, if I were going to have this equation: [math]n=>2, m=>2, p=>1, {p \times n}-{n \times m}[/math] With a limit to 1000, how would I encode this??? Link to comment Share on other sites More sharing options...
jordan Posted July 22, 2004 Share Posted July 22, 2004 Okay, allow me to restate it. The sigma code adds the solutions togather fopr the answer, e.g. [math]\sum_{q=0}^n (q+1)^2[/math'] if n was 2 the answer is 5. Sorry to digress from the topic for a minute, but wouldn't the answer be 14, or is it too late for me to be trying this stuff? Link to comment Share on other sites More sharing options...
Freeman Posted July 22, 2004 Author Share Posted July 22, 2004 No, the limit is two. There would be two equations starting with 0, so- (0+1)^2=1 (1+1)^2=4 1+4=5 QED ITs a little weird... Link to comment Share on other sites More sharing options...
jordan Posted July 22, 2004 Share Posted July 22, 2004 But if n=2, doesn't that mean continue through until q has been calculated for 2, thus adding 1+4+9? Link to comment Share on other sites More sharing options...
Freeman Posted July 22, 2004 Author Share Posted July 22, 2004 No, you calculate it only twice... Not until q=2. I did the same thing when I learned it at first Link to comment Share on other sites More sharing options...
Freeman Posted July 22, 2004 Author Share Posted July 22, 2004 So, is it possible to have a set as an answer? What equation would this be? Link to comment Share on other sites More sharing options...
Dave Posted July 22, 2004 Share Posted July 22, 2004 No, you calculate it only twice... Not until q=2. I did the same thing when I learned it at first No you don't, it's inclusive. Link to comment Share on other sites More sharing options...
YT2095 Posted July 22, 2004 Share Posted July 22, 2004 Dave, in my calculus book, they use a different symbol for Sum of, it looks like a long S of a fancy f without the line through the middle, is this the same as Sigma? that symbol and `d` are the only I`ve read about yet, `d` being "a little bit of" like dx would be a little bit of x and Sdx would be the sum of all the little bits of x is Sigma the same as the long S? Link to comment Share on other sites More sharing options...
Dave Posted July 22, 2004 Share Posted July 22, 2004 In a sense. What you're talking about is the integral symbol - which is hopefully what I'll be covering in my calculus threads fairly soon if I can get around to writing the next one. Imagine you have a curve, then draw equally spaced lines under the curve so that you can approximate the area under the curve by summing the areas of the trapezia that you've just drawn. Now if you decrease the height of the trapezia and take the limit of the series as the height tends to zero, that's your integral. Link to comment Share on other sites More sharing options...
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