Worksheet 1 Key

1. Factor (into linear factors)

(a)                                  (b) 

    Ans: (x- 6)(x- 1)                                         Ans: (x- 5)(x+5)


(c)                                  (c) 

    Ans: (3x- 1)(2x+1)                                     Ans: (x)(3x- 1)(x+1)
2. Simplify as much as possible

(a)                                              (b) 

Ans:                    Ans: 3. Let . Find the following (and simplify your answer as much as possible).

(a) 

Ans: 


(b) 

Ans:  (c)  Ans:  (d)  Ans:  (e)  Ans:  
f)  Ans:  (g)  Ans: Use parts (f) and (d) to get
   
(h)  Ans: Use part (g) to get
   
(i)  Ans:   4. Find exact values. (You may use a chart for this for now, but be forewarned that on the quizzes and exams you will have to know the trigonometric values of the standard angles by memory.)

(a) 

Ans:    (b)  Ans:  (c)  Ans: (d)  Ans: -1   (e)                                          (f)                                             (g) 

            Ans:                                                 Ans:                                                            Ans:
                                                                                                
 

5. Estimate the following (use your calculator only to check your estimate)

(a) 

Ans: Since  is between and, but is closer to , a rough estimate is 
 

(b) 
 

Ans: Since 185° is between 180° and 210° , but is closer to 180° , a rough estimate is cos 185° » - 0.95


(c) 
 

Ans: Since 3 is between and p , but is closer to p , a rough estimate is cos 3 » - 0.95


(d) 
 

Ans: Since 1° is only very slightly larger that 0° , we estimate sin 1° » 0.01


6. Complete each right triangle

    (a)
 

Ans: Using either the Pythagorean Theorem or the similarity with the 3-4-5 right triangle, you find that the hypotenuse is 20 units long.


    (b)
 

Ans: Using either the Pythagorean Theorem or the fact that this is a 5-12-13 right triangle, you find that the unlabeled leg is 12 units long.


    (c)
 

Ans:
                       
 
7. Solve each inequality for x. You may give your solution using either inequality notation, interval notation, or by graphing on a number line.

(a)                                                                  (b) 
 

Ans:                                                                                     Ans:
                                                        
 


(c)                                                                     (d) 
 

Ans:                                                                                     Ans: