Binomial theorem
If the 6th term in the expansion of \[\huge [\frac{ 1 }{ x ^{8/3}}+ x^2\log _{10}x]^8\] is 5600 , then find x
I have attempted this question , it may take some minutes to post
\(k\) th term of \((a+b)^n\) : \[\binom{n}{\color{red}{k-1}} a^{n-(\color{Red}{k-1})} b^{\color{Red}{k-1}}\]
\(6\) th term of \((a+b)^8\) : \[\binom{8}{\color{red}{6-1}} a^{8-(\color{Red}{6-1})} b^{\color{Red}{6-1}}\]
\[\huge \left(\begin{matrix}8 \\ 5\end{matrix}\right) x ^{\frac{ -512 }{ 27 }}.(x ^{2}\log _{10}x)^{5}\]=5600
\[\huge x ^{\frac{ -512 }{ 27 }}.(x ^{2}\log _{10}x)^{5} = 100\]
doesn't look correct
how did you get \(\large x^{\frac{-512}{27}}\) ?
yeah i felt i was making a terrible mistake somewhere
yes a very silly mistake actually
hmm, x^{-8/3}^3
\[\large \left(a^m\right)^n = a^{m\times n}\]
-_- sry
\[\left(x^{-8/3}\right)^3 = x^{-8/3\times 3} = x^{-8}\]
\[\huge x ^{-8}.(x ^{2}\log _{10}x)^{5}=100\]
you should end up with \[\large x ^{-8}\cdot (x ^{2}\log _{10}x)^{5} = 100\]
it is a equation now i can solve that , thank you
careful, it looks tricky...
\[\huge x^{2} . \log ^{5}_{10}x = 100\]
its a multiple choice , so by trial and error i got 10 hmm how to do that subjectively
that looks good
x=10 makes the log thingy 1 and balances both sides so yeah..
so if it was a subjective paper how would we solve that
idk but it would be painful im sure
subjective paper?
yeah any method is not visible to me not subjective paper
he wants to solve it analytically @perl
oh :)
but its good to know methods , my logarithm will also be revised
i think i got it
show me how
no it isn't working well
I will post it as a new question
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