Researcher: In completing the argument table (3
rd
row of the 2
nd
column), you only use
properties
, but not yet
using properties
, why
not use properties
?
M
Eks-16
: I see in the example only properties
, written by Sir
Researcher: Oh yes, but as soon as you complete
the next column, there appear
properties
, what
underlies you write like that?
M
Eks-16
: When I write like that, I think
with can share one another, Sir
Researcher: If you look at the time you compile a
formal proof, election it's right,
but once compiling the next step
appears
, this step
is illogical, why do this?
M
Eks-16
: After I tried using it … I mean what I
fill in the table of informal arguments,
I think this is correct Sir, it turns out
this is wrong, sir, I have a bit of
difficulty utilizing the traits
and manipulate signs of inequality
sir
Researcher: Ok, thank you, I think you have shown
a persistent effort to do proofs,
hopefully for the next question you are
better.
From the results of the interview, it shows that
the third row of the second column, students have
tried to include the previous pieces of evidence with
categories and coding, but the pieces of evidence in
the form of arguments that have not guaranteed the
next trait, students have not used the properties of
. Then for the next column, students
have used the previous step, but the pieces of
evidence for the choice assumption category (AC)
and (DEF) are ”
”
becomes illogical, even though in the selection δ = ε
as in the column it shows that the student is right to
choose. Next in compiling formal evidence, the
steps in the first row up to the third row of students
have done correctly, by using triangular inequality
and properties
, but in the fourth row the
students repeated, making mistakes entering “
”,so this formal proof
becomes invalid.
In general, from the results of the analysis of
student work for question number 1, several
obstacles can be found which cause student
difficulties in proving, as follows: (1) When
completing the informal argument table, students
cannot yet utilize the general nature of
and
, (2) Make mistakes in selection δ and
manipulate the nature of inequality ≤ to be <
(obstacle to manipulating algebraic forms), (3)
Students have difficulty utilizing the concepts
related to the questions to be proven, and (4)
Students have difficulty connecting informal
arguments and rewriting them into formal proof.
4 CONCLUSIONS
In general, from the results of the analysis of student
work, several obstacles can be found which give rise
to student difficulties in proof, namely when
completing the informal argument table, students
were not able to take advantage of the general nature
of |cos x | ≤ 1, making mistakes in the selection δ do
proof construction into formal proof, manipulate the
nature of inequality ≤ to be (obstacle to
manipulating algebraic forms), students have
difficulty utilizing concepts related to the questions
to be proven, students have difficulty connecting
informal arguments and rewriting them into formal
proof, and in the final settlement in constructing
proofs of students experiencing obstacles in using
the previous steps to formulate formal proof.
REFERENCES
Brousseau, G. 1997. Theory of didactical situations in
mathematics. Dordrecht: Kluwer academic publisher.
Cornu, B. 1991. Limits. In D. Tall (Ed.), Advanced
mathematical thinking. (pp. 153-166). Dordrecht:
Kluwer Academic Publishers.
Dubinsky, E. 1991. Reflective abstraction in advanced
mathematical thinking. In D. Tall (Ed.), Advanced
mathematical thinking (pp. 95-126). Dordrecht:
Kluwer academic publishers.
Hanna, G. 1995. Challenges to the importance of proof.
For the Learning of Mathematics, 15(3), 42–49.
Knuth, E. J. 2002. Secondary school mathematics teachers'
conceptions of proof. Journal for Research in
Mathematics Education, 33(5):379-405.
Magajna, Z. 2013. Overcoming the Obstacle of Poor
Knowledge in Proving Geometry Tasks, Journal
Centre for Educational Policy Studies. 3(4), 99-115.
Identifying Mathematics Education Studentsâ
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Z Obstacles in Reading and Constructing Proof in Real Analysis Courses
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