Tg(x+75) - tg(x+15) упростить

Решение tg(x+75) - tg(x+15) = [sin(x + 75 - x - 15)]/[cos75cos15] =  = sin60/[cos(90 - 15)*cos15)] = ( √3/2) / [sin15*cos15] =   (√3) / [2*sin15*cos15] =  √3 / sin30 = √3/(1/2) = 2√3