A boy stands 12 metres from the foot of the building and observes the angle of elevation of the top of the building. The height is of the building is approximately

Find the directions in which the function increases and decreases most rapidly at upper p 0p0. then find the derivatives of the function in these directions. f(x,y)equals=x squared plus xy plus y squaredx2+xy+y2, upper p 0p0left parenthesis 1 comma negative 4 right parenthesis