>>37
> calc =\(BC=4,aA=pi/4,aC=pi/8){
+ pB=0i
+ pC=BC+0i
+ f=\(x){
+ pA=x+1i*(-tan(aC)*(x-BC))
+ (angle(pB,pA,pC) - aA)^2
+ }
+ f=Vectorize(f)
+ x0=optimize(f,c(-BC,BC))$minimum
+ pA=x0+1i*(-tan(aC)*(x0-BC))
+ ABC2S(pA,pB,pC)
+ }
> calc()
[1] 4