It makes sense to let the # of shirts sold be the variable dependent upon the unit cost per shirt.
Notice that the # sold declines as the price increases.
Thus, the slope of this line will be -.
8000 - 5000 3000 shirts
m = ------------------- = ----------------- = -200 shirts per dollar price increase
25 - 40 -15
Answer:
By the distributive property:
105 + 35m = 35(3 + m)
What is the Converse of the Pythagorean Theorem? The theorem states that if the square of the length of the longest side of a triangle is equal to the sum of the squares of the other two sides, then the triangle is a right triangle
ANSWER TO QUESTION 1
The given function is

The partial derivative of f with respect to x means we are treating y as a constant. The first derivative is

and the second derivative with respect to x is,

ANSWER TO QUESTION 2
The given function is

The partial derivative of f with respect to y means we are treating x as a constant. The first derivative is

and the second derivative with respect to y is

ANSWER TO QUESTION 3
Our first mixed partial is

We need to differentiate

again. But this time with respect to y.
Since this is a product of two functions of y, we apply the product rule of differentiation to obtain,


ANSWER TO QUESTION 4
The second mixed partial is

We need to differentiate

again. But this time with respect to x.
Since this is a product of two functions of x, we apply the product rule of differentiation to obtain,


Hence,