The lines represented by the equations y
=
−
1
5
x
−
4
y=−
5
1
​
x−4 and
y
−
1
5
x
=
−
7
y−
5
1
​
x=−7 are

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