Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Problem 6 (3 marks). Without the use of calculators or software establish which number is larger: 
log_(189)1323 or 
log_(63)147.

Without the use of calculators or software establish which number is larger: \newlinelog1891323\log_{189}1323 or log63147\log_{63}147.

Full solution

Q. Without the use of calculators or software establish which number is larger: \newlinelog1891323\log_{189}1323 or log63147\log_{63}147.
  1. Use Change of Base Formula: Use the change of base formula to compare the two logarithms.\newlinelog1891323=log(1323)log(189)\log_{189}1323 = \frac{\log(1323)}{\log(189)}\newlinelog63147=log(147)log(63)\log_{63}147 = \frac{\log(147)}{\log(63)}
  2. Simplify Bases and Numbers: Simplify the bases and the numbers inside the logarithms by finding common factors.\newline189=33×7189 = 3^3 \times 7\newline63=32×763 = 3^2 \times 7\newline1323=33×721323 = 3^3 \times 7^2\newline147=3×72147 = 3 \times 7^2
  3. Cancel Common Factors: Simplify the expressions by canceling out common factors.\newlinelog1891323=log(3372)log(337)\log_{189} 1323 = \frac{\log(3^3 \cdot 7^2)}{\log(3^3 \cdot 7)}\newlinelog63147=log(372)log(327)\log_{63} 147 = \frac{\log(3 \cdot 7^2)}{\log(3^2 \cdot 7)}
  4. Apply Power Rule: Use the power rule of logarithms to bring down the exponents.\newlinelog1891323=3log(7)+2log(7)3log(3)+log(7)\log_{189}1323 = \frac{3 \cdot \log(7) + 2 \cdot \log(7)}{3 \cdot \log(3) + \log(7)}\newlinelog63147=log(3)+2log(7)2log(3)+log(7)\log_{63}147 = \frac{\log(3) + 2 \cdot \log(7)}{2 \cdot \log(3) + \log(7)}
  5. Combine Terms: Combine the terms with common logarithms.\newlinelog1891323=5log(7)3log(3)+log(7)\log_{189}1323 = \frac{5 \cdot \log(7)}{3 \cdot \log(3) + \log(7)}\newlinelog63147=2log(7)+log(3)2log(3)+log(7)\log_{63}147 = \frac{2 \cdot \log(7) + \log(3)}{2 \cdot \log(3) + \log(7)}
  6. Compare Numerators and Denominators: Compare the numerators and denominators of both expressions.\newlineFor log1891323\log_{189}1323, the numerator is 5×log(7)5 \times \log(7) and the denominator is 3×log(3)+log(7)3 \times \log(3) + \log(7).\newlineFor log63147\log_{63}147, the numerator is 2×log(7)+log(3)2 \times \log(7) + \log(3) and the denominator is 2×log(3)+log(7)2 \times \log(3) + \log(7).
  7. Correct Comparison Mistake: Notice that the numerator of log1891323\log_{189}1323 is larger than the numerator of log63147\log_{63}147, since 5 \times \log(7) > 2 \times \log(7) + \log(3). However, the denominator of log1891323\log_{189}1323 is also larger than the denominator of log63147\log_{63}147, since 3 \times \log(3) + \log(7) > 2 \times \log(3) + \log(7).
  8. Correct Comparison Mistake: Notice that the numerator of log1891323\log_{189}1323 is larger than the numerator of log63147\log_{63}147, since 5 \times \log(7) > 2 \times \log(7) + \log(3). However, the denominator of log1891323\log_{189}1323 is also larger than the denominator of log63147\log_{63}147, since 3 \times \log(3) + \log(7) > 2 \times \log(3) + \log(7). Since both the numerator and denominator of log1891323\log_{189}1323 are larger than those of log63147\log_{63}147, we cannot directly conclude which fraction is larger without further simplification or numerical evaluation.
  9. Correct Comparison Mistake: Notice that the numerator of log1891323\log_{189}1323 is larger than the numerator of log63147\log_{63}147, since 5 \times \log(7) > 2 \times \log(7) + \log(3). However, the denominator of log1891323\log_{189}1323 is also larger than the denominator of log63147\log_{63}147, since 3 \times \log(3) + \log(7) > 2 \times \log(3) + \log(7). Since both the numerator and denominator of log1891323\log_{189}1323 are larger than those of log63147\log_{63}147, we cannot directly conclude which fraction is larger without further simplification or numerical evaluation. Realize that a mistake was made in the previous step. The comparison of the numerators and denominators was incorrect. We need to correct this and compare the values properly.

More problems from Product property of logarithms