Solving an equation with trigonometrics...

On 07/06/2010 11:29 AM, Julien Martin wrote:
> Hello,
>
> I need to solve the following equation in order to find the value of
> "y" using Maxima:
>
> x=-1/2*arctan(y/2)+3*%pi/8;
>
> I would like to get a value of "y" instead of this:
> [arctan(y/2)=(3*%pi-8*x)/4]
>
> Can anyone help please?
>
> Thanks in advance,
>
> Julien.
You can see the associated maxima functions by typing

(%i11) display2d: false;

(%o11) false
(%i12) apropos("sin");

(%o12) [asin,asinh,decreasing,increasing,maxpsinegint,maxpsiposint,poisint,
 
PSInv_1,PSInv_1_usg,require_posinteger,sin,sinh,sinsert,sinvertcase,
         svd,svd_a,Sing_vals_usg,?%piargs\-sin\/cos]
(%i13) ? asin;

  -- Function: asin (<x>)
      - Arc Sine.


   There are also some inexact matches for `asin'.
   Try `?? asin' to see them.
(%i16) apropos("tan");

(%o16) 
[constant,atan,atan2,atanh,constantp,intanalysis,integration_constant,
         integration_constant_counter,pmin_dist,point_list_distance_usg,
         pmax_dist,point_list_max_distance_usg,rectangle,resultant,tan,tanh,
         ?%atan2,?%piargs\-tan\/cot]
(%i17) ? atan;

  -- Function: atan (<x>)
      - Arc Tangent.


   There are also some inexact matches for `atan'.
   Try `?? atan' to see them.

(%o17) true

HTH,
  -sen