Try It Yourself#

Exercise 1#

The weekly demand for Math-Hero video games is given by

\[p=x^3−150x+1000\]

where \(x\) is the number of video games produced and sold, and \(p\) is in dollars. Using the marginal revenue function, \(R'(x)\), approximate the marginal revenue when 10 Math-Hero video games have been produced and sold and interpret the result.

Show answer

Answer: \(\$2000\), revenue increases by about \(\$2000\) when weekly sales increase from 10 to 11

Exercise 2#

The weekly demand for Math Wars - Return of the Calculus video games is given by

\[p= \frac{250}{x-5} + 3500\]

where \(x\) is the number thousands of video games produced and sold, and \(p\) is in dollars.

Using the marginal revenue function, \(R'(x)\), approximate the marginal revenue when 10,000 video games have been produced and sold and interpret the result.

Show answer

Answer: \(\$3450\), revenue increases by about \(\$3450\) when weekly sales increase from 10,000 to 11,000

Exercise 3#

The daily cost (in dollars) of producing LCD ultra-high definition televisions is given by

\[C(x)= 5x^3 - 50x^2 + 50x + 2500\]

where \(x\) denotes the number of thousands of televisions produced in a day.

Using the marginal average cost function, \(\overline{C}'(x)\), approximate the marginal average cost when 5000 televisions have been produced and interpret the result.

Show answer

Answer: \(-\$100\), average cost decreases by about \(\$100\) when production increases from 5000 to 6000

Exercise 4#

Given the demand equation

\[p + \dfrac{x}{5} = 40,\]

where \(p\) represents the price in dollars and \(x\) the number of units, determine the elasticity of demand when the price \(p\) is equal to $20 and interpret the result.

Show answer

Answer: \(E(20) = 1\), unitary demand and total revenue is maximized

Exercise 5#

The demand for a product is given by

\[f(p) = 6 + \dfrac{7}{p}.\]

Determine the elasticity when \(p = 3\) and interpret the result.

Show answer

Answer: \(E(3) = \frac{7}{25}\), inelastic demand

Exercise 6#

Given the demand equation \(p = 12 - \dfrac{x^2}{25}\), determine the price \(p\) at which demand is unitary.

Show answer

Answer: \(p = 8\)

Exercise 7#

Given the demand equation

\[p + 5x = 20,\]

determine the price \(p\) at which total revenue is maximized.

Show answer

Answer: \(p = 10\)