Вычислите: cos(arctg(-3/4)+arcctg(-1/√3))

Question

Вычислите: cos(arctg(-3/4)+arcctg(-1/√3))

Answer 1

cos(arctg(-3/4)-П/3)=cos(п/3)*cos(arctg(-3/4)+sinП/3*sin(arctg(-3/4))=

=1/2*(-4/5)+sqrt(3)/2*3/5=(3sqrt(3)-4)/10