Binomial expansion in the form $(1+x^2)^n$ I'm used to dealing with binomial expansion in the form $(1+x)^n$. I understand that if the number is not $1$ then you have to divide the whole bracket by something which would make it $1$. However I'm not too sure how to deal with an $x^2$ in the bracket. Can I just work through it as usual using the binomial expansion formula, or do I have to take the square out so it is in the form $(1+x)^n$ ?

No, you can do it as usual $$\left(1+f(x)\right)^n=\sum_{k=0}^n\dbinom{n}{k}f(x)^k$$ where $f(x)$ can be equal to anything: $x^2, x^{1000}, \cos x, \frac{\ln x}{x}$ etc.
