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)e−bt /2a + 2 v(t )e−bt /2a . a 4a Then, by substituting in Eq. (1), we obtain b b2 b a v (t ) − v (t ) + 2 v(t ) + b v (t ) − v(t ) + cv(t ) e−bt /2a = 0. a 2a 4a (15) (16) Canceling the factor exp(−bt /2a ), which is nonzero, and rearranging the remaining terms, we find that a v (t ) + (−b + b)v (t ) + b2 b2 − + c v (t ) = 0. 4a 2a (17) The term involving v (t )is obviously zero. Further, the coefficient of v(t ) is c − (b2 /4a ), which is also zero because b2

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dispostos em bandas de cores alternadas, desde bandas mente, conforme podemos observar no mapa geológico de cor cinza-claro, ricas em quartzo e feldspatos, até simplificado do Quadrilátero Ferrífero (Fig. 2). Ao combandas escuras, ricas em biotita (Fig. 4A). Esses gnaisses pararmos a imagem de satélite (Fig. 1) com o mapa geológico (Fig. 2) podemos observar feições comuns. A região central do Quadrilátero Ferrífero é constituída por rochas do Complexo Granito-Gnáissico e Supergrupo Rio…