Math Problem Statement

Evaluate the logarithmic expressions: (a) log_8(1/8) and (b) log 1000.

Solution

Let's analyze and solve the two logarithmic expressions given in the image:

(a) log8(18)\log_8 \left(\frac{1}{8}\right)

This is a logarithmic expression in base 8, and we need to find the value of:

log8(18)=x\log_8 \left(\frac{1}{8}\right) = x

By the definition of logarithms, this means:

8x=188^x = \frac{1}{8}

We know that 18=81\frac{1}{8} = 8^{-1}, so we can rewrite the equation as:

8x=818^x = 8^{-1}

Since the bases are the same, we can equate the exponents:

x=1x = -1

Thus, log8(18)=1\log_8 \left(\frac{1}{8}\right) = -1.

(b) log1000\log 1000

Here, the expression is using a logarithm with no explicit base, meaning it's a common logarithm with base 10:

log1000=x\log 1000 = x

This means:

10x=100010^x = 1000

Since 1000=1031000 = 10^3, we have:

10x=10310^x = 10^3

Equating the exponents:

x=3x = 3

Thus, log1000=3\log 1000 = 3.

Final Answers:

  • (a) log8(18)=1\log_8 \left(\frac{1}{8}\right) = -1
  • (b) log1000=3\log 1000 = 3

Would you like a more detailed explanation or have any further questions?

Here are some related questions you might find interesting:

  1. How can we express log8(64)\log_8(64) in terms of a simple number?
  2. What is the general relationship between logarithms with different bases?
  3. Can you solve log2(32)\log_2(32) without using a calculator?
  4. How do we simplify expressions like log3(27)\log_3(27)?
  5. What happens when we solve logarithmic expressions with decimal numbers, like log(0.01)\log(0.01)?

Tip: Remember that logarithms are exponents. The equation logb(x)=y\log_b(x) = y means that by=xb^y = x, so logarithmic problems can often be solved by equating powers!

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Math Problem Analysis

Mathematical Concepts

Logarithms
Exponents

Formulas

log_b(x) = y implies b^y = x
Common logarithms (log base 10)

Theorems

Definition of Logarithms
Exponential Equivalence Theorem

Suitable Grade Level

Grades 9-11