30 jun 2015, 15:31
30 jun 2015, 16:50
30 jun 2015, 17:21
skaa Escreveu:\(=\frac{x-y}{\frac{1}{x^2}-\frac{1}{y^2}}=\frac{x-y}{\frac{y^2-x^2}{x^2y^2}}=\frac{x^2y^2(x-y)}{(y-x)(y+x)}=-\frac{x^2y^2}{x+y}\)
porque
\(\frac{x-y}{y-x}=-1\)
30 jun 2015, 19:49
01 jul 2015, 01:43