COS1501/201/0/2023
Tutorial letter 201/0/2023
Theoretical Computer Science 1
COS1501
Year module
School of Computing
This tutorial letter contains
a discussion of assessment 01 type questions.
, Dear Student,
Your assessment 1 that you did online on the system had similar questions, but the options may
have been in a different order,but all questions are covered. Below, a discussion to explain
some of the concepts. This is a practical module in which you apply theory. Therefore, you have
to make sure that you understand the underlying theory for assessments and the exam.
Regards,
COS1501 Team
DISCUSSION of ASSESSMENT 01
Question 1 Alternative 3
The different number sets are described in Chapter 1 and 2. Also see the Glossary of symbols
in the Introduction chapter of the study guide. In this question we have to determine which one
of the alternatives is false.
1. Z≥ Z
2. Z+ Z≥
3. R Q
4. Z+ R
Z = {... -4, -3, -2, -1, 0, 1, 2, 3, 4, ...}
c = {0, 1, 2, 3, 4, ...}
Z+ = {1, 2, 3, 4, ...}
From the diagram below it is clear that all elements in Z+ is also in the set Z≥ , and all elements
in Z≥ is also in the set Z etc.
We can therefore say that Z+ Z≥ Z Q R
From here we can see that alternative 3 is false, because Q is in R.
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