Chapter 6 Elementary Functions

Section 6.7 Final Test

6.7.1 Final Test Module 6

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Exercise 6.7.1
Specify the maximum domains Df and Dg of the two functions

f:  { Df →ℝ x⟼ 9 x2 -sin(x)+42 x2 -2

and

g:  { Dg →ℝ y⟼ ln(y) y2 +1  .


Exercise 6.7.2
Specify the range Wi of the function

i:  { ℝ→ℝ x⟼ x2 -4x+4+π .


Exercise 6.7.3
Find the parameters A,λ∈ℝ in the exponential function

c:  { ℝ→ℝ x⟼A·eλx -1  ,

such that c(0)=1 and c(4)=0.  
Answer: A  = 
, λ  = 
.  
Simple logarithms can be left as they are, e.g. ln(100) can be entered as ln(100) even though the exact value of ln(100) is unknown.

Exercise 6.7.4
Specify the composition h=f∘g:ℝ→ℝ (note: h(x)=(f∘g)(x)=f(g(x))) of the functions

f:  { ℝ→ℝ x⟼C·sin(x)

and

g:  { ℝ→ℝ x⟼B·x+π .

Answer: h(x)  = 
.  
Find the parameters such that the sine wave described by the function h has the graph shown below.
Abbildung 1: A sine wave.

 
Answer: h(x)  = 
.

Exercise 6.7.5
Specify the inverse function f= u-1 of

u:  { (0;∞)→ℝ y⟼- log2 (y) .

The function f= u-1 has
  1. the domain Df  =  .
  2. the range Wf  =  .
  3. the mapping rule f(y)= u-1 (y)  =  .
Enter the ranges as intervals of the form (a;b), infinity can also be an endpoint.

Exercise 6.7.6

Please indicate whether the following statements are right or wrong:  

The function

f:  { [0;3)→ℝ x⟼2x+1


  ... can be also written for short as f(x)=2x+1.
  ... is a linear affine function.
  ... has the range ℝ.
  ... has the slope 2.
  ... can only take values greater or equal 1 and less than 7.
  ... has a graph that is a piece of a line.
  ... has at x=0 the value 1.
  ... has the domain ℝ.

Exercise 6.7.7
Calculate the following logarithms:
  1. ln(e5 · 1 e )  =  .
  2. log10 (0.01)  =  .
  3. log2 (2·4·16·256·1024)  =  .
 
        

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