Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>That summation symbol gives you a clue: you need a loop.</p> <p>What's <code>0!</code>? 1, of course. So your starting value for e is 1. </p> <p>Next you'll write a loop for n from 1 to some larger value (infinity might suggest a while loop) where you calculate each successive term, see if its size exceeds your epsilon, and add it to the sum for e.</p> <p>When your terms get smaller than your epsilon, stop the loop.</p> <p>Don't worry about user input for now. Get your function working. Hard code an epsilon and see what happens when you change it. Leave the input for the last bit.</p> <p>You'll need a good factorial function. (Not true - thanks to Mat for reminding me.)</p> <p>Did you ask where the constant e comes from? And the series? The series is the Taylor series expansion for the exponential function. See any intro calculus text. And the constant e is simple the exponential function with exponent 1.</p> <p>I've got a nice Java version working here, but I'm going to refrain from posting it. It looks just like the C function will, so I don't want to give it away.</p> <p>UPDATE: Since you've shown yours, I'll show you mine:</p> <pre><code>package cruft; /** * MathConstant uses infinite series to calculate constants (e.g. Euler) * @author Michael * @link * @since 10/7/12 12:24 PM */ public class MathConstant { public static void main(String[] args) { double epsilon = 1.0e-25; System.out.println(String.format("e = %40.35f", e(epsilon))); } // value should be 2.71828182845904523536028747135266249775724709369995 // e = 2.718281828459045 public static double e(double epsilon) { double euler = 1.0; double term = 1.0; int n = 1; while (term &gt; epsilon) { term /= n++; euler += term; } return euler; } } </code></pre> <p>But if you ever need a factorial function I'd recommend a table, memoization, and the gamma function over the naive student implementation. Google for those if you don't know what those are. Good luck.</p>
    singulars
    1. This table or related slice is empty.
    1. POHow to Approximate e in an Infinite Series in C
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USduffymo
    1. USduffymo
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COYou don't need a factorial function at all. Just compute it in the loop, saving the last value.
      singulars
      1. PO
      1. USMat
    2. COWhile it's true factorial function is not needed, we can make it work first, then make it fast. It's easier to think in term of factorial function also.
      singulars
      1. PO
      1. USnhahtdh
    3. COAbsolutely true, Mat. I'll amend my answer.
      singulars
      1. PO
      1. USduffymo
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload