College Algebra, 4th Edition

Applying the Concepts

1. 91.

   1. Cost function

   2. Revenue function

   3. Selling price of x shirts after sale tax

   4. Profit function

2. 93.

   1. $P(x)=20x-350$

   2. $P(20)=50;$ profit made after 20 radios were sold

   3. 43

   4. $(R\circ x)(C)=5C-1,750.$ The function represents the revenue in terms of the cost C.

3. 95.

   1. $f(x)=0.7x$

   2. $g(x)=x-5$

   3. $(g\circ f)(x)=0.7x-5$

   4. $(f\circ g)(x)=0.7(x-5)$

   5. $1.50

4. 97.

   1. $f(x)=1.1x;g(x)=x+8$

   2. $(f\circ g)(x)=1.1x+8.8;$ a final test score, which originally was x, after adding 8 points and then ­increasing the score by 10%

   3. $(g\circ f)(x)=1.1x+8;$ a final test score, which originally was x, after increasing the score by 10% and then adding 8 points

   4. 85.8 and 85.0

   5. No

   6. 1. 3.82

      2. 4.55

5. 99.

   1. $f(x)=\pi x^2$

   2. $g(x)=\pi {(x+30)}^2$

   3. The area between the fountain and the fence

   4. $16,052

6. 101.

   1. $(f\circ g)(t)=\pi {(2t+1)}^2$

   2. $A(t)=\pi {(2t+1)}^2$