Вправи 201 - 342 » 247

247. Подайте у вигляді дробу вираз: 1) a–2 + a–3 = 1^(\a)/a^2 + 1/a^3 = (a+1)/a^3 ; 2) mn–4 + m–4n = m^(\m^4 )/n^4 + n^(\n^4 )/m^4 = (m^5+ n^5)/(n^4 m^4 ); 3) (c–1 – d–1)(c – d)–2 = (1^(\d)/c – 1^(\c)/d) • 1/((c-d)^2 ) = (d-c)/cd • 1/((c-d)^2 ) = –((c-d) • 1)/(cd(c-d)^2 ) = –1/cd(c-d) = 1/(cd(d-c)); 4) (x–2 + y–2)(x2 + y2)–1 = (1/x^2 + 1/y^2 ) • 1/(x^2+ y^2 ) = (x^2+ y^2)/(x^2 y^2 ) • 1/(x^2+ y^2 ) = 1/(x^2 y^2 ).