Answer:
We want to expand the expression:
[tex](x - \frac{1}{x^2} )^4[/tex]
We can just do it by brute force, this is:
First, rewrite our expression as the product of two square factors:
[tex](x - \frac{1}{x^2} )^4 = (x - \frac{1}{x^2} )^2*(x - \frac{1}{x^2} )^2[/tex]
Now we can expand each one these two factors:
[tex](x - \frac{1}{x^2} )^2 = (x - \frac{1}{x^2} )*(x - \frac{1}{x^2} ) = x^2 + \frac{1}{x^4} -2*x*\frac{1}{x^2}[/tex]
That can be simplified to
[tex]x^2 - \frac{2}{x} + \frac{1}{x^4}[/tex]
Now we can replace that in our original expression to get:
[tex](x^2 - \frac{2}{x} + \frac{1}{x^4})*(x^2 - \frac{2}{x} + \frac{1}{x^4})[/tex]
Now we can expand that last product, to get:
[tex](x^2)^2 + 2*(x^2)*(-\frac{2}{x} ) + 2*(x^2)*(\frac{1}{x^4}) + 2*(\frac{-2}{x})*(\frac{1}{x^4}) + (\frac{-2}{x} )^2 + (\frac{1}{x^4})^2[/tex]
We can simplify that to:
[tex]x^4 - 4x + 2x^2 - \frac{4}{x^5} + \frac{4}{x^2} + \frac{1}{x^8}[/tex]
That is the expanded expression.
