Help with Linear Algebra , Orthonormal Basis

Greetings , I'm new to the site and well , I have the following question.

In a polynominal space in the order smaller then 3 , a given standard basis is {1,x,x^2,x^3} , find the Orthonormal Basis.

(I had to translate the question from another language so forgive me for any mistakes made in the translation)

Basically I've been a real slacker on my algebra course so now I have study by myself :P .

Anyways , I think the answer is {1,x+x^2+x^3} but im not sure , nor do I have a proper solution , so if possible I'd like to ask for a proper full solution.

Help would be much appriciated , Thanks.