Try It Yourself#

Exercise 1#

Marginal revenue

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.

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

Exercise 2#

Marginal revenue

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.

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

Exercise 3#

Marginal average cost

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.

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

Exercise 4#

Elasticity of demand

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.

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

Exercise 5#

Elasticity of demand

The demand for a product is given by

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

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

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Answer: \(E(3) = 7/25\), inelastic demand

Exercise 6#

Unitary demand

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

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Answer: \(p = 8\)

Exercise 7#

Maximum revenue

Given the demand equation \(p + 5x = 20\), determine the price \(p\) at which total revenue is maximized.

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Answer: \(p = 10\)