transformations - inverse compact

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1. The diagram shows three graphs. y x B A C A is part of the graph of y = x. B is part of the graph of y = 2 x . C is the reflection of graph B in line A. Write down (a) the equation of C in the form y =f(x); (b) the coordinates of the point where C cuts the x-axis. 2. The diagrams show how the graph of y = x 2 is transformed to the graph of y = f(x) in three steps. For each diagram give the equation of the curve. y y y y 0 0 0 0 x x x x y=x 2 4 1 1 1 1 3 7 (a) (b) (c) 3. The diagram shows the graph of y = f(x), with the x-axis as an asymptote. 1

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Page 1: Transformations - Inverse Compact

1. The diagram shows three graphs.

y

x

B

A

C

A is part of the graph of y = x.

B is part of the graph of y = 2x.

C is the reflection of graph B in line A.

Write down

(a) the equation of C in the form y =f(x);

(b) the coordinates of the point where C cuts the x-axis.

2. The diagrams show how the graph of y = x2 is transformed to the graph of y = f(x) in three steps.

For each diagram give the equation of the curve.

y

y

y

y

0

0

0

0

x

xx

xy= x 2

4

1

1 1

1

3

7

(a )

(b ) (c )

3. The diagram shows the graph of y = f(x), with the x-axis as an asymptote.

1

Page 2: Transformations - Inverse Compact

A (– 5 , – 4 )

B (5 , 4 )

y

x

(a) On the same axes, draw the graph of y =f(x + 2) – 3, indicating the coordinates of the images of the points A and B.

(b) Write down the equation of the asymptote to the graph of y = f(x + 2) – 3.

4. The following diagram shows the graph of y = f (x). It has minimum and maximum points at

(0, 0) and ( 2

1,1

) .

– 2 – 1 0 1 2 3

3 .5

3

2 .5

2

1 .5

1

0 .5

– 1

– 1 .5

– 0 .5

– 2

– 2 .5

y

x

(a) On the same diagram, draw the graph of 2

3)1–( xfy

.

(b) What are the coordinates of the minimum and maximum points of

2

3)1–( xfy

?

(Total 4 marks)

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Page 3: Transformations - Inverse Compact

5. The diagram shows parts of the graphs of y = x2 and y = 5 – 3(x – 4)2.

2

4

6

8

– 2 0 2 4 6

y

x

y = x 2

2y x= 5 – 3 ( – 4 )

The graph of y = x2 may be transformed into the graph of y = 5 – 3(x – 4)2 by these transformations.

A reflection in the line y = 0 followed bya vertical stretch with scale factor k followed bya horizontal translation of p units followed bya vertical translation of q units.

Write down the value of

(a) k;

(b) p;

(c) q.

6. The sketch shows part of the graph of y = f(x) which passes through the points A(–1, 3), B(0, 2), C(l, 0), D(2, 1) and E(3, 5).

8

7

6

5

4

3

2

1

0

– 1

– 2

– 4 – 3 – 2 – 1 1 2 3 4 5

A

B

C

D

E

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Page 4: Transformations - Inverse Compact

A second function is defined by g(x) = 2f(x – 1).

(a) Calculate g(0), g(1), g(2) and g(3).

(b) On the same axes, sketch the graph of the function g(x).

7. (a) The diagram shows part of the graph of the function f(x) = .

– px

q

The curve passes through the point A (3, 10). The line (CD) is an asymptote.

y

x

1 5

1 5

1 0

1 0

5

50

– 5

– 5

– 1 0

– 1 0

– 1 5

– 1 5

A

C

D

Find the value of

(i) p;

(ii) q.

(b) The graph of f(x) is transformed as shown in the following diagram. The point A is transformed to A (3, –10).

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Page 5: Transformations - Inverse Compact

y

x

1 5

1 5

1 0

1 0

5

50

– 5

– 5

– 1 0

– 1 0

– 1 5

– 1 5

A

C

D

Give a full geometric description of the transformation.

8. Let f(x) = 2x + 1.

(a) On the grid below draw the graph of f(x) for 0 x 2.

(b) Let g(x) = f(x +3) –2. On the grid below draw the graph of g(x) for –3 x –1.

6

5

4

3

2

1

– 1

– 2

– 3

– 4

– 5

– 6

654321– 1– 2– 3– 4– 5– 6 0

y

x

5

Page 6: Transformations - Inverse Compact

9. The quadratic function f is defined by f(x) = 3x2 – 12x + 11.

(a) Write f in the form f(x) = 3(x – h)2 – k.

(b) The graph of f is translated 3 units in the positive x-direction and 5 units in the positive y-direction. Find the function g for the translated graph, giving your answer in the form g(x) =

3(x – p)2 + q.

10. The graph of y = f(x) is shown in the diagram.

2

1

– 1

– 2

– 2 – 1 1 2 3 4 5 6 7 8 x

y

0

(a) On each of the following diagrams draw the required graph,

(i) y = 2f(x);

2

1

– 1

– 2

– 2 – 1 1 2 3 4 5 6 7 8 x

y

0

(ii) y = f(x – 3).

2

1

– 1

– 2

– 2 – 1 1 2 3 4 5 6 7 8 x

y

0

(b) The point A (3, –1) is on the graph of f. The point A is the corresponding point on the graph

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Page 7: Transformations - Inverse Compact

of y = –f(x) + 1. Find the coordinates of A.

11. Let f(x) = x, and g(x) = 2x. Solve the equation

(f –1 o g)(x) = 0.25.

12. Two functions f, g are defined as follows:

f : x 3x + 5g : x 2(1 – x)

Find

(a) f –1(2);

(b) (g o f)(–4).

13. Given functions f : x x + 1 and g : x x3, find the function (f ° g)–l.

14. The function f is defined by

.2

3,2–3: xxaxf

Evaluate f –1(5) .

15. Given that f(x) = 2e3x, find the inverse function f –1(x).

16. Let f(x) = 2x, and g(x) = 2–x

x

, (x 2).

Find

(a) (g ° f) (3);

(b) g–1 (5).

17. Consider the functions f : x 4 (x – 1) and g : x 2

–6 x

.

(a) Find g–1.

(b) Solve the equation (f ° g–1) (x) = 4.

18. Let f(x) = e–x, and g(x) = x

x

1 , x –1. Find

(a) f–1(x)

(b) (g ° f)(x).

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Page 8: Transformations - Inverse Compact

19. The function f is defined for x 0 by f(x) = 1

1–2

2

x

x

.

Find an expression for f–1(x).

20. The set of all real numbers Runder addition is a group ( , +), and the set + of all positive real

numbers under multiplication is a group ( +, ×). Let f denote the mapping of ( , +) to ( +, ×)

given by f(x) = 3x.

(a) Show that f is an isomorphism of ( , +) onto ( +, ×).(6)

(b) Find an expression for f–1.

21. The function f is given by f(x) = x2 – 6x + 13, for x 3.

(a) Write f(x) in the form (x – a)2 + b.

(b) Find the inverse function f–1.

(c) State the domain of f–1.

22. Let f(x) = 2x + 1 and g(x) = 3x2 – 4.

Find

(a) f–1(x);

(b) (g f )(–2);

(c) (f g)(x).

23. The functions f and g are defined by 2:,3: xxgxf .

(a) Find an expression for (f g) (x).

(b) Show that f–l (18) + g–l (18) = 22.

24. The functions f and g are defined by f : x ex, g : x x + 2.

(a) Calculate f–1(3) × g–1(3).

(b) Show that (f ° g)–1(3) = ln 3 – 2.

25. The function f is given by f(x) = e(x–11) –8.

(a) Find f–1(x).

(b) Write down the domain of f–l(x).

26. The function f is defined for x > 2 by f(x) = ln x + ln (x – 2) – ln (x2 – 4).

(a) Express f(x) in the form ln(x/(x+a)).

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Page 9: Transformations - Inverse Compact

(b) Find an expression for f–1(x).

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