How to read log Table
- 2. L o g T a b l e I NT RO D U C T IO N PART 1
- 3. Enter title Before finding the logarithm of a number, we should know about the characteristics and mantissa part of a given number
- 4. Enter title Characteristic Part– The whole part of a number is called the characteristic part. The characteristic of any number greater than one is positive, and if it is one less than the number of digits to the left of the decimal point in a given number. If the number is less than one, the characteristic is negative and is one more than the number of zeros to the right of the decimal point.
- 5. M a n t i s s a P a r t The decimal part of the logarithm number is said to be the mantissa part and it should always be a positive value. If the mantissa part is in a negative value, then convert into t h e p o s i t i v e v a l u e .
- 6. How to Use the L o g T a b l e ? PART 2
- 7. Enter title Step 1: Understand the concept of the logarithm. Each log table is only usable with a certain base. The most common type of logarithm table is used is log base 10.
- 8. Enter title Step 2: Identify the characteristics and mantissa part of the given number. For example, if you want to find the value of log10 (15.27), first separate the characteristic part and the mantissa part. Characteristic Part = 15 Mantissa part = 27
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- 10. Enter title Step 3: Use a common log table. Now, use row number 15 and check column number 2 and write the corresponding value. So the value obtained is 1818.
- 11. Enter title Step 4: Use the logarithm table with a mean difference. Slide your finger in the mean difference column number 7 and row number 15, and write down the corresponding value as 20.
- 12. Enter title Step 5: Add both the values obtained in step 3 and step 4. That is 1818+20= 1838. Therefore, the value 1838 is the mantissa part.
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- 14. Enter title Step 6: Find the characteristic part. Since the number lies between 10 and 100, (10¹ and 10² ), the characteristic part should be 1.
- 15. Enter title Step 7: Finally combine both the characteristic part and the mantissa part, it becomes 1.1838.
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- 17. S a m p l e E x a m p l e PART3
- 18. Question: Find the value of log10 2.872 Step 1: Characteristic Part= 2 and mantissa part= 872
- 19. • Step 2: Check the row number 28 and column number 7. So the value obtained is 4579. • Step 3: Check the mean difference value for row number 28 and mean difference column 2. The value corresponding to the row and column is 3
- 20. • Step 4: Add the values obtained in step 2 and 3, we get 4582. This is the mantissa part. • Step 5: Since the number of digits to the left side of the decimal part is 1, the characteristic part is less than 1. So the characteristic part is 0
- 21. • Step 6: Finally combine the characteristic part and the mantissa part. So it becomes 0.4582. Therefore the value of log 2.872 is 0.4582.
- 22. THANK YOU