arctg(x)=p/24 если х=√6-√3+√2-2
и
arctg(x)=p/12 если х=(√3-1)/(√3+1)

tgπ/24=xtg²π/24=(1-cosπ/12)/1+cosπ/12)cos²π/12=(1+cosπ/6):2=(1+√3/2)*1/2=(2+√3)/4tg²π/24=?1)(1-√(2+√3)/2)/(1+√(2+√3)/2)=