Нужно 1)x=tg(arccos(-1/4)+pi/2) найти х 2) у=-2tg(x+pi/5) график

X=tg(arccos(-1/4)+π/2) = - ctg(arccos(-1/4) = 
    = - [cos(arccos(-1/4)]/[√(1-cos²(arccos(-1/4))]=
    = - (-1/4)/√(1-(-1/4)²) = (1/4)/(√15/4) = 1/√15 = √15/15
x=√15/15