(a) If there is a scalar function f(x, y) such that ∇ f(x, y) = x² i + y² j, then
∂f/∂x = x²
∂f/∂y = y²
Integrating both of these equations with respect to x and y (respectively) gives
f(x, y) = 1/3 x³ + g(y)
f(x, y) = 1/3 y³ + h(x)
Differentiating with respect to the other variable gives
∂f/∂y = g'(y) = y²
∂f/∂x = h'(x) = x²
so it follows that
f(x, y) = 1/3 x³ + 1/3 y³ + C
for some constant C.
(b) By the gradient theorem,

Answer: Number 4: 0.07, 60%, 13/20, 2/3, 0.70, and then 3/2
Step-by-step explanation:
Answer:
Option 3
Step-by-step explanation:
we are given the graph of a parabola
with vertex at (0,-1) and symmetrical about y axis and also open up.
Hence the equation of the graph would be transformation of 
by a vertical shift of 1 unit down.
So new equation after transformation would be

Or
Hence option 3 is right choice.
Verify:
Put Solving the equation we get


In the graph x intercepts are the same as -1 and 1
Hence our answer is right.
Given dimensions of a rectangular garden are:
length = 2(x+6) feet
width = 3.5x feet
using the distributive property on length we get, length = 2x+12
Perimeter of a rectangle is 2(length+width)
So, P = 2(2x+12+3.5x)
Solving it we get,
P = 2(5.5x +12) ..............adding like terms
P =
.............multiplying and adding
P = 11x+24
So, perimeter is 11x+24 feet. This value of fencing will be needed.
Answer:
b) 8 feet
Step-by-step explanation:
5+3=8
So, the answer will be 8