Can You Solve this Trig Inverse Equation with arctan and arctan?

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To solve the equation arctan(3x) + arctan(2x) = π/4, the identity arctan[x] + arctan[y] = arctan[(x+y)/(1-xy)] is applied. This simplifies to finding the angle whose tangent is 1, leading to the equation 5x/(1-6x^2) = 1. Solving this results in x = 1/6 and x = -1, but -1 is rejected since it falls outside the domain of arctan. Therefore, the valid solution is x = 1/6.
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Homework Statement


Solve arctan 3x + arctan 2x= pie/4?


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The Attempt at a Solution

 
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there is a trig identiy that helps.

arctan[x]+arctan[y] = arctan[(x+y)/(1-xy)]

then it is just the angle that has a tan of pi/4 (i am assuming radians), so 1

then solving 5x/(1-6x^2)=1 we get x= 1/6 and x=-1
reject the -1 as the domain of arctan does not include it if is re-inserted into the fuction.
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
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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