Date | November 2020 | Marks available | 2 | Reference code | 20N.1.SL.TZ0.T_11 |
Level | Standard Level | Paper | Paper 1 (with calculator from previous syllabus) | Time zone | Time zone 0 |
Command term | State | Question number | T_11 | Adapted from | N/A |
Question
The diagram shows the graph of the quadratic function f(x)=ax2+bx+c , with vertex (−2, 10).
The equation f(x)=k has two solutions. One of these solutions is x=2.
Write down the other solution of f(x)=k.
Complete the table below placing a tick (✔) to show whether the unknown parameters a and b are positive, zero or negative. The row for c has been completed as an example.
State the values of x for which f(x) is decreasing.
Markscheme
* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure. It appeared in a paper that permitted the use of a calculator, and so might not be suitable for all forms of practice.
(x=) (-2)-4 OR (x=) (-2)-(2-(-2)) (M1)
Note: Award (M1) for correct calculation of the left symmetrical point.
(x=) -6 (A1) (C2)
[2 marks]
(A1)(A1) (C2)
Note: Award (A1) for each correct row.
[2 marks]
x>-2 OR x≥-2 (A1)(A1) (C2)
Note: Award (A1) for -2 seen as part of an inequality, (A1) for completely correct notation. Award (A1)(A1) for correct equivalent statement in words, for example “decreasing when x is greater than negative 2”.
[2 marks]