Answer
$1+4x+6x^2+4x^3+x^4$
Work Step by Step
The formula to determine the binomial series is:
$(1+x)^p=1+\Sigma_{k=1}^\infty \dbinom{p}{k}x^k$
Here, $\dbinom{p}{k}=\dfrac{p(p-1)(p-2).....(p-k+1)}{k!}$
Now, $(1+x)^{4}=1+4x+\dfrac{(4)(3)x^2}{2!}+\dfrac{(4)(3)(2)x^3}{3!}+\dfrac{(4)(3)(2)(1)x^4}{4!}...$
Thus, the first four terms are: $1+4x+6x^2+4x^3+x^4$
