Calculating a limit with tangent as denominator

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To calculate the limit of (x^3 - 2x^2 + x)/tan(x) as x approaches 0, it is suggested to rewrite tan(x) as sin(x)/cos(x). This allows for the expression to be rearranged, facilitating the factoring of x from the numerator. By applying the limit properties, the expression can be simplified to (x/sin(x))(x^2 - 2x + 1)cos(x). Ultimately, the limit evaluates to 1 as x approaches 0. Understanding the correct application of limits and factoring is crucial for solving this type of problem.
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Homework Statement


lim x^3-2x^2+x/tanx
x->0


The Attempt at a Solution



All i know is that tan is going to break up into sinx/cosx so the equation will look like this

lim x^3-2x^2+x/(sinx/cosx)
x->0

I haven't worked with cubic or quadratic functions yet so I don't know where to begin with this.
 
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Tebow15 said:

Homework Statement


lim x^3-2x^2+x/tanx
x->0

Remember to throw in brackets where necessary, because the way it looks right now is

\lim_{x\to 0}\left(x^3-2x^2+\frac{x}{\tan(x)}\right)

So you need to put brackets around the cubic to avoid this confusion :wink:
Tebow15 said:

The Attempt at a Solution



All i know is that tan is going to break up into sinx/cosx so the equation will look like this

lim x^3-2x^2+x/(sinx/cosx)
x->0

I haven't worked with cubic or quadratic functions yet so I don't know where to begin with this.

If your problem is of the form \lim_{x\to a}\left(f(x)\cdot g(x)\right) then this is equivalent to \lim_{x\to a}f(x)\cdot\lim_{x\to a} g(x)

So try factoring out an x from the numerator, and see if you can apply this idea correctly.
 
I may have confused you with the way I wrote it, it should look like this. (I'll use brackets to make it clearer)

lim (x^3-2x^2+x)/(sinx/cosx)
x->0
 
The answer eventually = 1 but I don't know how to get there
 
Factor out x as Mentallic suggested and rearange the expression as

\left(\frac{x}{\sin(x)}\right)(x^2-2x+1)\cos(x)

ehild
 
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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