Solving a Polynomial: y=x^4/(x^2+1) and y=1/(x^2+1)

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In summary, the conversation discusses two curves: y = x^4 / (x^2 + 1) and y = 1 / (x^2 + 1). The attempt at a solution involves assuming the two equations are equal and then cross multiplying, but this method is incorrect. Instead, multiplying both sides by x^2 + 1 is recommended. The resulting polynomial can be factored to solve the problem.
  • #1
Asphyxiated
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Homework Statement



The curves are:

[tex] y = \frac{x^{4}}{x^{2}+1} [/tex]

and

[tex] y = \frac{1}{x^{2}+1} [/tex]

The Attempt at a Solution



So again I assume that:

[tex] \frac {x^{4}}{x^{2}+1} = \frac {1}{x^{2}+1} [/tex]

and then cross multiply:

[tex] (x^{2}+1) = x^{4}(x^{2}+1) [/tex]

not really sure at this point if i should distribute the x^4 but if i do it looks like so:

[tex] (x^{2}+1) = (x^{6}+x^{4}) [/tex]

so:

[tex] (x^{2}+1)-(x^{6}+x^{4}) = 0 [/tex]

and I am not really sure what to do at this point, I do have a polynomial if I do the subtraction which is:

[tex] -x^{6}-x^{4}+x^{2}+1 = 0 [/tex]

but I don't know how to factor it...

thanks guys!
 
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  • #2
Asphyxiated said:

Homework Statement



The curves are:

[tex] y = \frac{x^{4}}{x^{2}+1} [/tex]

and

[tex] y = \frac{1}{x^{2}+1} [/tex]


The Attempt at a Solution



So again I assume that:

[tex] \frac {x^{4}}{x^{2}+1} = \frac {1}{x^{2}+1} [/tex]

and then cross multiply:
Don't cross multiply. Multiply both sides by x^2 + 1.
Asphyxiated said:
[tex] (x^{2}+1) = x^{4}(x^{2}+1) [/tex]

not really sure at this point if i should distribute the x^4 but if i do it looks like so:

[tex] (x^{2}+1) = (x^{6}+x^{4}) [/tex]

so:

[tex] (x^{2}+1)-(x^{6}+x^{4}) = 0 [/tex]

and I am not really sure what to do at this point, I do have a polynomial if I do the subtraction which is:

[tex] -x^{6}-x^{4}+x^{2}+1 = 0 [/tex]

but I don't know how to factor it...

thanks guys!
 
  • #3
thanks man, worked out, but I am having a WAY hard time trying to do this problem so I will post the actual problem another thread. thanks for the help here though.
 

FAQ: Solving a Polynomial: y=x^4/(x^2+1) and y=1/(x^2+1)

What is a polynomial?

A polynomial is a mathematical expression that consists of variables, coefficients, and exponents, connected by operations such as addition, subtraction, multiplication, and division. It can have multiple terms and can be written in the form of an equation or function.

What is the degree of a polynomial?

The degree of a polynomial is the highest exponent of the variable in the expression. For example, in the polynomial y = 3x^2 + 2x + 1, the highest exponent is 2, so the degree of the polynomial is 2.

How do you solve a polynomial equation?

To solve a polynomial equation, you need to find the values of the variable(s) that make the equation true. This can be done by using various methods such as factoring, the quadratic formula, or graphing. In some cases, it may not be possible to find exact solutions, in which case approximate solutions can be found using numerical methods.

What is the difference between the two given polynomials?

The two given polynomials, y = x^4/(x^2+1) and y=1/(x^2+1), have different degrees and different terms. The first polynomial has a degree of 4 and consists of one term, while the second polynomial has a degree of 2 and consists of two terms. Additionally, the first polynomial is a rational function, while the second is a simple fraction.

How do you graph a polynomial function?

To graph a polynomial function, you can use either a graphing calculator or manually plot points on a coordinate plane. The x-coordinates of the points can be chosen based on any values, and the corresponding y-coordinates can be calculated by substituting the x-values into the polynomial function. The resulting points can then be connected to create a graph of the polynomial.

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