tan(arctan(1/3)+arctan(1/2))=(tanarctan(1/3)+tanarctan(1/2))/(1-tanarctan(1/3)*tanarctan(1/2))=(1/3+1/2)/(1-1/3*1/2)=(5/6) /(5/6)=1所以arctan(1/3)+arctan(1/2)=pai/4