[WP 34s] Trapezoidal approximation of area under curve
06-01-2015, 06:56 PM (This post was last modified: 06-01-2015 07:06 PM by Thomas Klemm.)
Post: #4
 Thomas Klemm Senior Member Posts: 1,542 Joined: Dec 2013
RE: [WP 34s] Trapezoidal approximation of area under curve
(06-01-2015 01:53 PM)Marcio Wrote:  If so, I am planning on creating a program that would take advantage of that so it would be possible to easily calculate the area under a curve defined by data, as shown below:

$\int_{x_1}^{x_n} y(x) dx \approx \frac{1}{2} \sum_{k=1}^{n-1} (x_{k+1}-x_{k})(y_{k+1}+y_{k})$

You could use something like:
Code:
001 LBL'TPZ' 002 CLΣ 003 LBL 00 004 STOP 005 R↑ 006 RCL+ Z 007 R↑ 008 RCL- Z 009 Σ+ 010 R↓ 011 R↓ 012 GTO 00 013 END

Usage:
$$y_1$$ ENTER $$x_1$$ XEQ'TPZ'
$$y_2$$ ENTER $$x_2$$ R/S
(...)
$$y_n$$ ENTER $$x_n$$ R/S
Σxy
-2 ÷

Not a sophisticated program but I hope you get the idea.

Cheers
Thomas
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 Messages In This Thread [WP 34s] Trapezoidal approximation of area under curve - Marcio - 06-01-2015, 01:53 PM RE: [WP 34s] Trapezoidal approximation of area under curve - Marcus von Cube - 06-01-2015, 03:54 PM RE: [WP 34s] Trapezoidal approximation of area under curve - Dave Britten - 06-01-2015, 05:36 PM RE: [WP 34s] Trapezoidal approximation of area under curve - Thomas Klemm - 06-01-2015 06:56 PM RE: [WP 34s] Trapezoidal approximation of area under curve - Dieter - 06-02-2015, 09:23 PM RE: [WP 34s] Trapezoidal approximation of area under curve - Marcio - 06-02-2015, 02:46 AM RE: [WP 34s] Trapezoidal approximation of area under curve - Marcio - 06-16-2015, 10:47 AM RE: [WP 34s] Trapezoidal approximation of area under curve - Dieter - 06-16-2015, 11:31 AM RE: [WP 34s] Trapezoidal approximation of area under curve - Thomas Klemm - 06-16-2015, 12:38 PM RE: [WP 34s] Trapezoidal approximation of area under curve - Marcio - 06-16-2015, 12:57 PM

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