Solving a triangle means finding all possible triangles when some of its sides a,b and c and angles A,B,C (A is the the angle opposite to a, and so on...) are known. This problem has 0, 1, 2 or infinitely many solutions.
I want to write a procedure to solve triangles. The user would feed the procedure with some datas amongst a,b,c,A,B,and C (if it is necessary for the sake of simplicity, you can assume that the user will avoid situations where there are infinitely many solutions) and the procedure will compute the other ones. The usual requires to use the Law of Sines or the Law of Cosines, depending on the situation.
Since it is for a Maths class where I also want to show graphs of functions, I will implement it in Maple. If Maple is not suitable for your answer, please suggest another language (I am reasonably competent in Java and beginner in Python for example).
My naive idea is to use conditional instructions if...then...else to determine the case in hand but it is a little bit boring. Java has a switch that could make things shorter and clearer, but I am hoping for a smarter structure.
Hence my question: Assume that some variables are related by known relations. Is there a simple and clear way to organize a procedure to determine missing variables when only some values are given?
PS: not sure on how I should tag this question. Any suggestion is welcome.
One approach could be to make all of the arguments to your procedure optional with default values that correspond to the names: A, B, C, a, b, c. Since we can make the assumption that all missing variables are those that are not of type 'numeric', it is easy for us to then quickly determine which variables do not yet have values and give those as the values to a solve command that finds the remaining sides or angles.
Something like the following could be a good start:
trisolve := proc( { side1::{positive,symbol} := A, side2::{positive,symbol} := B, side3::{positive,symbol} := C,
angle1::{positive,symbol} := a, angle2::{positive,symbol} := b, angle3::{positive,symbol} := c } )
local missing := remove( hastype, [ side1, side2, side3, angle1, angle2, angle3 ], numeric );
return solve( { 180 = angle1 + angle2 + angle3,
side1/sin(angle1*Pi/180)=side2/sin(angle2*Pi/180),
side1/sin(angle1*Pi/180)=side3/sin(angle3*Pi/180),
side2/sin(angle2*Pi/180)=side3/sin(angle3*Pi/180),
side1^2=side2^2+side3^2-2*side2*side3*cos(angle1) },
missing );
end proc:
The following call:
trisolve( side1 = 1, angle1 = 90, angle2 = 45 );
returns:
[B = (1/2)*sqrt(2), C = (1/2)*sqrt(2), c = 45]