Lessons 7–8 · 2 lessons · N. I. Taylaqov (general editor), A. B. Akhmedov, M. D. Pardayeva, A. A. Abdug‘aniyev, U. M. Mirsanov. Informatics and Information Technologies, Grade 10, 1st edition. “Extremum-Press”, Tashkent, 2017
7
The function arguments window
Textbook: pp. 20–22
GoalEnters a function through the Insert Function wizard and the Function Arguments window; uses LOG, LN, LOG10 and GCD.
New words
Insert Function: the wizard that finds a function and puts it in the cell · Insert Function (fx)Function Arguments window: the dialog with a field for each argument and a preview of the result · Function Arguments oynasilogarithm: the power to which the base must be raised to get the number · logarifmcollapse button: shrinks the dialog so that a range can be chosen with the mouse · diapazonni yig‘ish tugmasi
Explanation
If you cannot remember a function name, you find it through the wizard: press the fx button next to the formula bar, or Formulas – Insert Function (Shift+F3). In the first step you search for the function by description or choose a category; in the second step the Function Arguments window opens, with a separate field for each argument, a description of the function and a preview of the result. The button beside a field collapses the window so that a range can be chosen easily with the mouse. When you press OK, the finished formula goes into the cell. The logarithm function is written LOG(number, base): if no base is given, 10 is used; LN(x) is the natural logarithm (base e) and LOG10(x) the common logarithm. For example LOG(243, 3) = 5, because 3⁵ = 243.
Worked examples
Finding log₃ 243: fx → Math & Trig → LOG; 243 goes into the Number field and 3 into the Base field, the window shows “= 5”, and OK puts =LOG(243,3) in the cell. In the same way =LOG(8,2) = 3 and =LOG10(1000) = 3.
The greatest common divisor of 28, 42 and 70: fx → GCD; Number1 = 28, Number2 = 42, Number3 = 70. The window shows 14, because 28 = 2·14, 42 = 3·14, 70 = 5·14 and 2, 3, 5 have no common divisor except 1.
Class activity
“Call the wizard”: the teacher poses a task (“the logarithm of 64 to base 4”); students find the function through fx, fill in the argument fields and compare the preview in the window with the answer they calculated in their notebooks.
Practice
1
What is =LOG(81,3) and why?
4, because 3⁴ = 81.
2
What is the result of =LN(1)?
0
3
If no base is given, to which base is =LOG(100) calculated and what is the result?
base 10; the result is 2
4
Why is the Function Arguments window convenient for a complex function?
Each argument is entered in its own field and the description and a preview of the result are visible, so mistakes are less likely.