We substitute this into equation () and equate the coefficients belonging to the same frequency, keeping only the lowest-order terms.
wiː sˈʌbstɪtˌuːt ðɪs ˌɪntʊ ᵻkwˈeɪʒən ænd ɪkwˈeɪt ðə kˌoʊɪfˈɪʃənts bᵻlˈɔŋɪŋ tə ðə sˈeɪm fɹˈiːkwənsi, kˈiːpɪŋ ˈoʊnli ðə lˈoʊɪstˈɔːɹdɚ tˈɜːmz.