Question

ctg38×ctg22-1/ctg38+ctg22

Answer 1

$ctg( alpha + beta )= dfrac{ctg alpha cdot ctg beta -1}{ctg beta +ctg alpha }$

В нашем случае:

$dfrac{ctg38аcdot ctg22а-1}{ctg38а+ctg22а} =ctg(38а+22а)=ctg60а= dfrac{1}{sqrt{3}}$