The purpose of this study is to analyze the status of understanding on the definition and attribute of logarithms and to be helpful for improving the teaching method of the unit of logarithms.
For the purpose of this, the research question were set up...
The purpose of this study is to analyze the status of understanding on the definition and attribute of logarithms and to be helpful for improving the teaching method of the unit of logarithms.
For the purpose of this, the research question were set up as follows:
1. How is the understanding of the definition of logarithms by the inverse relationship of exponents?
a. How is the understanding of the definition of logarithms?
b. How is the calculation application by the definition of logarithms?
2. How is the understanding of the attribute of logarithms by the inverse relationship of exponents?
a. How is the understanding of the attribute of logarithms?
b. How is the calculation application by the attribute of logarithms?
In order to carry out this research, the researcher arbitrarily selected four schools of A and B high school located in Daejeon and C and D high school located in Nonsan-si, Chungnam and sampled 243 students from 8 classes, 2 classes of 2nd graders each from those high schools.
The tool of examination was produced referring to the textbook and precedent studies of the 7th Educational Curriculum. Analyzing the results of preliminary tests, the problems of test papers were modified and complemented. The questions selected for this research were 12 questions, and 4 scopes of contents which are the understanding of the definition of logarithms, the calculation application on the definition of logarithms, the understanding on the attribute of logarithms and the calculation application on the attribute of logarithms were divided and analyzed. The analysis results were presented by the scopes of each question.
On this foundation, I drew the conclusion of this study like the following.
First, in the question to ask the definition of logarithms by the inverse relationship of exponents, the percentage of correct answers were 74. 07%(180 students), and also in the question offered by concrete numerical formula, a high percentage of correct answers was shown. What was shown through solving process, they tended to simplify the expressions by using the attribute of logarithms rather than to find out the equivalent expressions. It indicates that the students are familiar with the use of logarithm symbols by mechanical transformation like arithmetic symbols as tools and the use of the attribute of logarithms.
In the question of presenting the condition of base and antilogarithm to define the logarithms, most of the students learned the condition by heart without understanding the condition of base and antilogarithm by use of exponents. It’s because they think of exponents and logarithms as different ones. Accordingly, many students did not understand the relationship of exponents and logarithms.
In conclusion, in order to understand the definition of logarithms, it is necessary to understand the previous unit on the understanding on exponents and the understanding on bases and exponents from the unit of logarithms and the relationship of bases and antilogarithms. However, the students are familiar with the use of the attribute of logarithms instead of understanding the relationship between exponential definition and logarithmic definition. Not only using logarithm as a tool, they should understand the relationship between exponents and logarithms exactly. In order to do that, it is necessary to help them understand the definition of logarithms associated with the forms of logarithms and exponents.
Secondly, in the questions to explain the attribute of logarithms by exponents, the percentage of correct answers was 18.63%, that is, many students did not explain the attribute of logarithms by exponents. It indicates that students depend on simple memorizing to study the attribute of logarithms. It is judged that the standard of understanding the attribute is quite low.
The questions to investigate whether they can calculate the expressions of the four arithmetical operations by use of the attribute of logarithms were provided. The rate of correct answers was 60% on the average. The percentage of correct answers for the question to ask the attribute of logarithm log_(a)x-log_(a)y=log_(a)x/y was the lowest among the questions. Like this, we could know that the students knew that the addition and subtraction of logarithms is transformed into multiplication and division, but in the calculation to multiply or divide antilogarithms, they did not understand the attribute of logarithms exactly. Moreover, incomparison with the questions for the understanding of the attribute of logarithms, the questions of calculation applications showed comparatively high rate of correct answers. Therefore, as they depended on memorizing, they tended to answer without consistency according to types of question.
However, the percentage of correct answers for the questions to explain the attribute of logarithms by use of the inverse relationship of exponents was more than 90%, and the types of incorrect answers were examined. As a result, in comparison with the students who failed to explain the attribute, the rate of the students who made mistakes to apply the attribute was very low. Therefore, the teachers should guide the students to understand the attribute of logarithms through the inverse relationship with exponents, not just to understand it by memorizing. The teachers should teach the student to exactly understand the relationship between the logarithmic summation(log_(a)x+log_(a)y=log_(a)xy) and the multiplication of exponents(a^(x)a^(y)=a^(x+y)), and the relationship between logarithmic scalar multiplication(plog_(a)x=log_(a)x^(p)) and (a^(x))^(p)=a^(xp). Therefore, the teachers should help the students understand the law of exponents in connection with those attributes. In addition, the teachers should try to arouse the students’ interest and curiosity about the attribute of logarithms by explaining the historical backgrounds of it.