If x - \(\frac{1}{x}\) = 1, find \(\left(\frac{1}{x-1}-\frac{1}{x+1}+\frac{1}{x^2+1}-\frac{1}{x^2-1}\right)\) |
±\(\sqrt {5}\) ±\(\frac{2}{\sqrt {5}}\) 0 ±\(\frac{2}{5}\) |
±\(\frac{2}{\sqrt {5}}\) |
\(\left(\frac{1}{x-1}-\frac{1}{x+1}+\frac{1}{x^2+1}-\frac{1}{x^2-1}\right)\) = \(\frac{x+1-x+1}{(x+1)(x-1)}+\frac{1}{x^2-1}-\frac{1}{x^2-1}\) ⇒ \(\frac{2}{x^2-1}+\frac{1}{x^2+1}-\frac{1}{x^2-1}\) ⇒ \(\frac{1}{x^2-1}+\frac{1}{x^2+1}\) ⇒ \(\frac{x^2+1+x^2-1}{x^4-1}\) =\(\frac{2x^2}{x^4-1}\) ⇒ \(\frac{2x^2}{x^2(x^2-\frac{1}{x^2})}\) =\(\frac{2}{x^4-\frac{1}{x^2}}\) .....(1) Now x - \(\frac{1}{x}\) = 1 x + \(\frac{1}{x}\) = \(\sqrt {1+4} = \sqrt {5}\) Put in (1) \(\frac{2}{(1)(\sqrt {5})}\) ±\(\frac{2}{\sqrt {5}}\) |