Why Does This Logarithmic Trigonometric Equation Equal Zero?

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The discussion revolves around the logarithmic trigonometric equation involving the tangent function and its summation equating to zero. Participants analyze the steps taken to prove that the sum of logarithms of tangent values from 1° to 89° equals zero, ultimately leading to the conclusion that the product of these tangent values equals one. A critical error identified is the incorrect assumption that the logarithmic function can be separated linearly, which is not generally true. Additionally, there is a mention of a problem with the middle term in the series, as the logarithm of tan 45° is undefined. The conversation emphasizes the need for careful handling of logarithmic properties in trigonometric identities.
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Homework Statement
Prove,
##\frac{1}{\log_{tan\ 1^\circ}(2021)} +\frac{1}{\log_{tan\ 2^\circ}(2021)} +\frac{1}{\log_{tan\ 3^\circ}(2021)} +...+\frac{1}{\log_{tan\ 89^\circ}(2021)} = 0 ##
Relevant Equations
-
The attempt at a solution

##

{\log_{2021}(tan\ 1^\circ)} +{\log_{2021}(tan\ 2^\circ)} +{\log_{2021}(tan\ 3^\circ)} +...+{\log_{2021}(tan\ 89^\circ)} = 0 \\

Antilog_{2021}[{\log_{2021}(tan\ 1^\circ)} +{\log_{2021}(tan\ 2^\circ)} +{\log_{2021}(tan\ 3^\circ)} +...+{\log_{2021}(tan\ 89^\circ)} ] = Antilog_{2021}[0]\\
tan\ 1^\circ + tan\ 2^\circ + tan\ 3^\circ +...+ tan\ 89^\circ = 1\\
arctan(tan\ 1^\circ + tan\ 2^\circ + tan\ 3^\circ +...+ tan\ 89^\circ = 1)\\
1^\circ +2^\circ +3^\circ +...+89^\circ = 45^\circ \\
\frac{89}{2} \times 90^\circ=45^\circ \\
##
Where did I make mistake?
I also want to know How to display a long equation in the same line in MathJax(Ex. 2nd line)
 
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Manasan3010 said:
Problem Statement: Proof,
The above should be Prove.
You prove (verb) a statement to arrive at a proof (noun).
Manasan3010 said:
##\frac{1}{\log_{tan\ 1^\circ}(2021)} +\frac{1}{\log_{tan\ 2^\circ}(2021)} +\frac{1}{\log_{tan\ 3^\circ}(2021)} +...+\frac{1}{\log_{tan\ 89^\circ}(2021)} = 0 ##
Relevant Equations: -

Working

##

{\log_{2021}(tan\ 1^\circ)} +{\log_{2021}(tan\ 2^\circ)} +{\log_{2021}(tan\ 3^\circ)} +...+{\log_{2021}(tan\ 89^\circ)} = 0 \\

Antilog_{2021}[{\log_{2021}(tan\ 1^\circ)} +{\log_{2021}(tan\ 2^\circ)} +{\log_{2021}(tan\ 3^\circ)} +...+{\log_{2021}(tan\ 89^\circ)} ] = Antilog_{2021}[0]##
The line below has an error.
##f(a + b + c) \ne f(a) + f(b) + f(c)##, in general.
Manasan3010 said:
##tan\ 1^\circ + tan\ 2^\circ + tan\ 3^\circ +...+ tan\ 89^\circ = 1\\
arctan(tan\ 1^\circ + tan\ 2^\circ + tan\ 3^\circ +...+ tan\ 89^\circ = 1)\\
1^\circ +2^\circ +3^\circ +...+89^\circ = 45^\circ \\
\frac{89}{2} \times 90^\circ=45^\circ \\
##
Where did I make mistake?
I also want to know How to display a long equation in the same line in MathJax(Ex. 2nd line)
 
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Mark44 said:
The line below has an error.
f(a+b+c)≠f(a)+f(b)+f(c)f(a+b+c)≠f(a)+f(b)+f(c)f(a + b + c) \ne f(a) + f(b) + f(c), in general.
Which line are you referring to and What should I to get the correct steps?
 
Manasan3010 said:
Which line are you referring to and What should I to get the correct steps?
The second and third lines of your work.
Manasan3010 said:
##Antilog_{2021}[{\log_{2021}(tan\ 1^\circ)} +{\log_{2021}(tan\ 2^\circ)} +{\log_{2021}(tan\ 3^\circ)} +...+{\log_{2021}(tan\ 89^\circ)} ] = Antilog_{2021}[0]##
The line below doesn't follow from the line above.
Manasan3010 said:
##tan\ 1^\circ + tan\ 2^\circ + tan\ 3^\circ +...+ tan\ 89^\circ = 1##
You are in essence saying that ##f(a + b + c) = f(a) + f(b) + f(c)##, which is generally not true.

Start in again with your first line:
##\log_{2021}(\tan 1^\circ) +\log_{2021}(\tan 2^\circ) +\log_{2021}(\tan 3^\circ) +...+\log_{2021}(\tan 89^\circ) = 0##

Use the idea that ##\log_b(A) + \log_b(B) = \log_b(AB)##
 
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I found the solution Thanks.

If anyone looking for solution Then,
tan1 .tan2 .tan3……tan87 .tan88. tan89

tan1 . tan 2 . tan 3 ….. cot3. cot 2. cot 1

tan1.cot1 . tan2.cot2 …..tan44.cot44. tan45

1*1*1*1…….1
 
There's actually an issue with the problem as stated. The middle term of the series would be
$$\frac 1{\log_{\tan 45^\circ}2021},$$ but the logarithm is undefined since there's no power of 1 that's equal to 2021.
 
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Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks

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