Date | None Specimen | Marks available | 4 | Reference code | SPNone.1.hl.TZ0.7 |
Level | HL only | Paper | 1 | Time zone | TZ0 |
Command term | Show that | Question number | 7 | Adapted from | N/A |
Question
Consider the following system of equations:
x+y+z=1
2x+3y+z=3
x+3y−z=λ
where λ∈R .
Show that this system does not have a unique solution for any value of λ .
(i) Determine the value of λ for which the system is consistent.
(ii) For this value of λ , find the general solution of the system.
Markscheme
using row operations, M1
to obtain 2 equations in the same 2 variables A1A1
for example y−z=1
2y−2z=λ−1
the fact that one of the left hand sides is a multiple of the other left hand side indicates that the equations do not have a unique solution, or equivalent R1AG
[4 marks]
(i) λ=3 A1
(ii) put z=μ M1
then y=1+μ A1
and x=−2μ or equivalent A1
[4 marks]