tdf#123192 - Improve help for function ATAN2

updated text in ATAN2 section of 04060106.xhp
added coordinates-to-polar-01.svg
changed example and image
removed 'Important!', added 'radians'
changed 'LibreOffice' to '%PRODUCTNAME'
created new folder 'scalc' under 'media/helpimg/'
moved coordinates-to-polar-01.svg to new folder
and added the path/image name to Package_html_media.mk
droped xml-lang="en-US" tag, removed 'Note',
removed '<pre>' tag, did not add <embed> as
Jenkins rejects it.

Change-Id: I5cff6289e8ab25f511e7d31ba2d4ad733dea184a
Reviewed-on: https://gerrit.libreoffice.org/67619
Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>

1 files changed, 16 insertions, 7 deletions

diff --git a/source/text/scalc/01/04060106.xhp b/source/text/scalc/01/04060106.xhp
index 25c822517c..c2f40d1c8b 100644
--- a/source/text/scalc/01/04060106.xhp
+++ b/source/text/scalc/01/04060106.xhp
@@ -221,18 +221,27 @@
 <bookmark xml-lang="en-US" branch="hid/SC_HID_FUNC_ARCTAN2" id="bm_id3159180" localize="false"/>
 
 <paragraph id="hd_id3153983" role="heading" level="2" xml-lang="en-US">ATAN2</paragraph>
-<paragraph id="par_id3154297" role="paragraph" xml-lang="en-US"><ahelp hid="HID_FUNC_ARCTAN2">Returns the inverse trigonometric tangent of the specified x and y coordinates.</ahelp></paragraph>
-
+<paragraph id="par_id3154297" role="paragraph" xml-lang="en-US"><ahelp hid="HID_FUNC_ARCTAN2">Returns the angle (in radians) between the x-axis and a line from the origin to the point (NumberX|NumberY).</ahelp></paragraph>
+<embed href="text/scalc/01/ODFF.xhp#odff"/>
 <embed href="text/scalc/01/common_func.xhp#sectionsyntax"/>
 <paragraph id="par_id3156013" role="code" xml-lang="en-US">ATAN2(NumberX; NumberY)</paragraph>
-<paragraph id="par_id3151168" role="paragraph" xml-lang="en-US"><emph>NumberX</emph> is the value of the x coordinate.</paragraph>
+<paragraph id="par_id3001800" role="paragraph" xml-lang="en-US"><emph>NumberX</emph> is the value of the x coordinate.</paragraph>
 <paragraph id="par_id3152798" role="paragraph" xml-lang="en-US"><emph>NumberY</emph> is the value of the y coordinate.</paragraph>
-<paragraph id="par_id5036164" role="paragraph" xml-lang="en-US">ATAN2 returns the inverse trigonometric tangent, that is, the angle (in radians) between the x-axis and a line from point NumberX, NumberY to the origin. The angle returned is between -PI and PI.</paragraph>
-<paragraph id="par_id3001800" role="paragraph" xml-lang="en-US">To return the angle in degrees, use the DEGREES function.</paragraph>
+<tip id="par_id5036168">Programming languages have usually the opposite order of arguments for their atan2() function.</tip>
+<paragraph id="par_id5036165" role="paragraph" xml-lang="en-US">ATAN2 returns the angle (in radians) between the x-axis and a line from the origin to the point (NumberX|NumberY)</paragraph>
 
 <embed href="text/scalc/01/common_func.xhp#sectionexample"/>
-<paragraph id="par_id3154692" role="paragraph" xml-lang="en-US"><item type="input">=ATAN2(20;20)</item> returns 0.785398163397448 (PI/4 radians).</paragraph>
-<paragraph id="par_id1477095" role="paragraph" xml-lang="en-US"><item type="input">=DEGREES(ATAN2(12.3;12.3))</item> returns 45. The tangent of 45 degrees is 1.</paragraph><comment>see also COS, SIN, TAN, COT, ACOS, ASIN, ATAN, ACOT</comment>
+<paragraph id="par_id3154692" role="paragraph" xml-lang="en-US"><item type="input">=ATAN2(-5;9)</item> returns 2.07789 radians.</paragraph>
+
+<paragraph id="par_id5036166" role="paragraph" xml-lang="en-US">To get the angle in degrees apply the DEGREES function to the result.</paragraph>
+<paragraph id="par_id1477095" role="paragraph" xml-lang="en-US"><input>=DEGREES(ATAN2(12.3;12.3))</input> returns 45. The tangent of 45 degrees is 1.</paragraph><comment>see also COS, SIN, TAN, COT, ACOS, ASIN, ATAN, ACOT</comment>
+<note id="par_id5036167">%PRODUCTNAME results 0 for ATAN2(0;0).</note>
+
+<paragraph id="par_id5036169" role="paragraph" xml-lang="en-US">The function can be used in converting cartesian coordinates to polar coordinates.</paragraph>
+<paragraph id="par_id5036170" role="paragraph" xml-lang="en-US">=DEGREES(ATAN2(-8;5)) returns &#966; =  147.9 degrees</paragraph>
+<paragraph role="paragraph" id="par_id5036171" xml-lang="en-US">
+<image id="img_id3150758" src="media/helpimg/scalc/coordinates-to-polar-01.svg" width="2.5inch" height="1.5inch"><alt id="alt_id3150758" xml-lang="en-US">Cartesian coordinates to polar coordinates example</alt></image>
+</paragraph>
 <embed href="text/scalc/06/calcsamplefiles.xhp#trigon"/>
 </section>