Justin and his friends dan went to movie if they each bought popcorn for 4.25 and a soda for 2.25 what was their total bill after adding 5% sales tax

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