T-QAD Day 13 @ 29 April 2020

Notes Topic: Functions

Subtopic: Composite functions

 T-QAD for TODAY

Question 1 : Q1/D13/290420

Given the functions f(x) = p - 2x and g(x) = 3x² – 7  

find the value of p if fg(2) = 4. 

                                                                                    (3 marks)

Question 2 : Q2/D13/290420

The function g is defined by  g(x) = x + 3  and the  function f is such 

that fg(x) = x² + 6x + 7. 

Find,

a) the function f

b) the value of k for which  f(2k) = 8k + 30

                                                                                    (6 marks)

Answers T-QAD 28 April 2020

Check your answer and fill in the form to record your marks.

MyMarks 

Question 1

Marks for sketching : 
Construct table for x and f(x) for 0 till 6.             K1
Identify f(x) = 0 at x = 2.5                                    K1
Plot correctly all points                                        K1
Connect all points with straight line. V shaped   K1

Range of f(x)    :    0 ≤ f(x) ≤ 7                             N1


Question 2
a)

Marks for sketching : 

Construct table for x and f(x) for -1 till 5.             K1
plot correctly  and Identify f(x) = 0 at x = 2          K2
Connect all points with straight line. V shaped   K1

Draw g(x) correctly using any method                 K2

b)  0 ≤ x ≤ 3            N1