Is This Solution Correct for f(x)=(x²)(ln x)(cos x)?

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The discussion revolves around the confusion regarding how to "solve" the function f(x)=(x²)(ln x)(cos x). Participants emphasize the need for clarity in the question, suggesting that the original poster likely meant to find the derivative rather than solve for a value. There is a strong indication that the provided answer, exp(2/x + 1/x ln x - tan x), does not align with standard derivative solutions. The conversation highlights the importance of clearly stating mathematical problems and the appropriate methods to approach them. Overall, the thread underscores the necessity of understanding derivative rules when dealing with composite functions.
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does anybody knows how to solve this:f(x)=(x^2) (ln x) (cos x) ??

i would like to know the final answer is it = exp (2/x + 1/x ln x - tan x)??
 
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We can't tell you the answer if you won't tell us the question! I don't know what you mean by "solve f(x)= ". Since you titled this "derivatives" I might guess you mean "find the derivative of f(x)" but in that case your "answer" makes no sense at all. I can only guess that you means something else entirely.

Please state the question clearly and don't just show an answer, show us how you got it.
 
ya,that's the question...myanswer it wrong.May i know how to do it??
 
I'll repeat:Please state the question clearly and don't just show an answer, show us how you got it.

I really doubt that you have a homework problem that says, word for word, "solve f(x)=(x^2) (ln x) (cos x)". It makes no sense to say "solve" a function.

Now, how did you attempt to do this problem?
 
Do you know that d(uv)/dx = v(du/dx) + u(dv/dx)
Now here you have three functions. Can you take two functions as one and then apply the above rule again i.e. apply it two times.
 
Have they move teaching about derivatives, to precalculus courses? :confused:
 
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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