Calculating a limit with tangent as denominator

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Homework Help Overview

The problem involves calculating the limit of the expression (x^3 - 2x^2 + x) divided by tan(x) as x approaches 0. The subject area pertains to limits in calculus, particularly involving trigonometric functions.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss rewriting the tangent function in terms of sine and cosine, and some suggest factoring out x from the numerator. There are questions regarding the correct interpretation of the limit expression and the importance of using brackets for clarity.

Discussion Status

Participants are exploring different ways to manipulate the limit expression and clarify its structure. Suggestions have been made to factor and rearrange the expression, but there is no explicit consensus on a final approach or solution yet.

Contextual Notes

Some participants note that they are not familiar with cubic or quadratic functions, which may affect their ability to approach the problem effectively. There is also a mention of the need for clarity in notation to avoid confusion in the limit expression.

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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

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

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 [tex]\lim_{x\to a}\left(f(x)\cdot g(x)\right)[/tex] then this is equivalent to [tex]\lim_{x\to a}f(x)\cdot\lim_{x\to a} g(x)[/tex]

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

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

ehild
 

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