Difference between revisions of "005 Sample Final A, Question 7"

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''' Question ''' Solve the following equation, &nbsp;&nbsp;&nbsp;&nbsp; <math> 2\log_5(x) = 3\log_5(4)</math>
 
''' Question ''' Solve the following equation, &nbsp;&nbsp;&nbsp;&nbsp; <math> 2\log_5(x) = 3\log_5(4)</math>
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{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
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!Foundations
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|-
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|1) What logarithm rule is relevant for dealing with the coefficients of the logarithms?
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|-
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|2) How do we remove the logs?
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|-
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|Answer:
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|-
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|1) One of the rules of logarithms says that <math> r\log(x) = \log(x^r)</math>
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|2) The definition of logarithm tells us that if <math> \log_5(x) = y </math>, then <math> 5^y = x </math>
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|}
  
  

Latest revision as of 20:22, 21 May 2015

Question Solve the following equation,      Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 2\log_5(x) = 3\log_5(4)}

Foundations
1) What logarithm rule is relevant for dealing with the coefficients of the logarithms?
2) How do we remove the logs?
Answer:
1) One of the rules of logarithms says that Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle r\log(x) = \log(x^r)}
2) The definition of logarithm tells us that if Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \log_5(x) = y } , then Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 5^y = x }


Step 1
Use the rules of logarithms to move the 2 and the 3 to exponents. So Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \log_5(x^2) = \log_5(4^3)}
Step 2
By the definition of logarithm, we find that Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle x^2 = 4^3}
Step 3
Taking the square root of both sides we get Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle x = 8}
Final Answer
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle x = 8}