A= 30;                 b= 25;                 c=  40;                 a =sqrt(b^2 + c^2 - 2 * b * c * cos(A));                 echo ("line 56 ",A,B,C,a,b,c); works, I guess a given value is wrong. On 10/05/2021 22:20, lar3ry wrote: > Thanks! Got another problem with a formula. Here's a snippet > >         if (formula==43) { >                 A=given[0]; // 30 >                 b=given[4]; // 25 >                 c=given[5]; // 40 >                 a =sqr(b^2 + c^2 - 2 * b * c * cos(A)); >                 echo ("line 56 ",A,B,C,a,b,c); > > and the result of the echo is: > ECHO: "line 56 ", 30, 0, 0, 242999, 25, 40 > > The answer should be 22.20 according to the http://cossincalc.com > <http://cossincalc.com> site. > >     nophead wrote >     If you mean sin to the -1 it means arcsine, which is asin() in > openscad. >     I.e. the inverse of sin. > >     > What the heck does the '-1' in that formula mean? > ------------------------------------------------------------------------ > Sent from the OpenSCAD mailing list archive > <http://forum.openscad.org/> at Nabble.com. > > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org

The square root function is sqrt(). You've got sqr(). -- Sent from: http://forum.openscad.org/

Hmm... A= 30; b= 25; c= 40; a =sqr(b^2 + c^2 - 2 * b * c * cos(A)); echo ("line 56 ",A,B,C,a,b,c); ECHO: "line 56 ", 30, 0, 0, 242999, 25, 40 This is with OpenSCAD version 2021.04.21.ai7788 (git d9d4a9757) Exactly the same result with OpenSCAD version 2019.05 A= 30; b= 25; c= 40; a =sqr((b*b) + (c*c) - 2 * b * c * cos(A)); echo ("line 56 ",A,B,C,a,b,c); ECHO: "line 56 ", 30, 0, 0, 242999, 25, 40 I am unable to test with 2021.01 because on the OpenSCAD download page, sudo apt-get install openscad gives me 2019.05 mondo wrote >     A= 30; >                 b= 25; >                 c=  40; >                 a =sqrt(b^2 + c^2 - 2 * b * c * cos(A)); >                 echo ("line 56 ",A,B,C,a,b,c); > > works, I guess a given value is wrong. > > > On 10/05/2021 22:20, lar3ry wrote: >> Thanks! Got another problem with a formula. Here's a snippet >> >>         if (formula==43) { >>                 A=given[0]; // 30 >>                 b=given[4]; // 25 >>                 c=given[5]; // 40 >>                 a =sqr(b^2 + c^2 - 2 * b * c * cos(A)); >>                 echo ("line 56 ",A,B,C,a,b,c); >> >> and the result of the echo is: >> ECHO: "line 56 ", 30, 0, 0, 242999, 25, 40 >> >> The answer should be 22.20 according to the http://cossincalc.com >> &lt;http://cossincalc.com&gt; site. >> >>     nophead wrote >>     If you mean sin to the -1 it means arcsine, which is asin() in >> openscad. >>     I.e. the inverse of sin. >> >>     > What the heck does the '-1' in that formula mean? >> ------------------------------------------------------------------------ >> Sent from the OpenSCAD mailing list archive >> &lt;http://forum.openscad.org/&gt; at Nabble.com. >> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to > discuss-leave@.openscad > > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to > discuss-leave@.openscad -- Sent from: http://forum.openscad.org/

That loud sound you just heard was my hand slapping my forehead! Thanks Len! LenStruttmann wrote > The square root function is sqrt(). You've got sqr(). -- Sent from: http://forum.openscad.org/