---
title: "iemisc: Additional Examples from GNU Octave Compatible cosd Function"
author: "Irucka Embry, E.I.T. (EcoC²S)"
date: "`r Sys.Date()`"
lang: en-us
urlcolor: blue
output:
  rmarkdown::pdf_document:
    highlight: kate
    toc: true
    latex_engine: xelatex
vignette: >
  %\VignetteIndexEntry{iemisc Additional Examples from GNU Octave Compatible cosd Function}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

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# cosd Examples (R style)

```{r, warning = FALSE, message = FALSE, tidy = TRUE}

library("iemisc")

# Examples from GNU Octave cosd

cosd(c(0, 180, 360))


cosd(c(90, 270, 45))



try(cosd(pi * seq(0, 80, by = 10) / 180))
# gives error message since the computed value is in radians rather than degrees


cos(pi * seq(0, 80, by = 10) / 180)
# this is correct since `cos` expects the angle in radians

try(cosd(seq(0, 80, by = 10) * 180 / pi))
# converts angles in radians to degrees; however, it will still receive an error message with this current implementation. You can use the work-around below:

xx <- seq(0, 80, by = 10) * 180 / pi

cosd(xx)


try(cos(seq(0, 80, by = 10) * 180 / pi))
# converts angles in radians to degrees; however, this is incorrect since `cos` expects the angle in radians and not degrees


cosd(90)

cos(pi/2)
```

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# cosd and cos Examples (GNU Octave style)

```{octave eval = FALSE}

cosd(90)

cos(pi/2)



% results

>> cosd(90)
ans = 0
>>
>> cos(pi/2)
ans =    6.1232e-17
>>
```

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## Works Cited

Design Guide No. 1110-1-3: Air Stripping Engineering and Design Appendix D: Example Air Stripping By Packed Column, Department Of The Army U.S. Army Corps of Engineers, 31 October 2001, pages D-1 - D-18, http://www.publications.usace.army.mil/Portals/76/Publications/EngineerDesignGuides/DG_1110-1-3.pdf?ver=2013-08-16-101222-003.  

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# EcoC²S Links

EcoC²S Home -- https://www.ecoccs.com/  
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R Trainings and Resources provided by EcoC²S (Irucka Embry, E.I.T.) -- https://www.ecoccs.com/rtraining.html  

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# Copyright and License

All R code written by Irucka Embry is distributed under the GPL-3 (or later) license, see the [GNU General Public License {GPL} page](https://www.gnu.org/licenses/gpl-3.0.html).  

All written content originally created by Irucka Embry is copyrighted under the Creative Commons Attribution-ShareAlike 4.0 International License. All other written content retains the copyright of the original author(s).  

This work is licensed under a [Creative Commons Attribution-ShareAlike 4.0 International License](https://creativecommons.org/licenses/by-sa/4.0/).  
